This does a few clean-ups.  With this PR, all spark.ml tree components have ```private[ml]``` constructors.

CC: mengxr

Author: Joseph K. Bradley <joseph@databricks.com>

Closes #5567 from jkbradley/dt-api-dt2 and squashes the following commits:

2263b5b [Joseph K. Bradley] Added note about tree example issue.
bb9f610 [Joseph K. Bradley] Small cleanups after original tree API PR

1. Clearly specifies the contract/interactions for users of this class.
2. Minor fix in one doc to avoid ambiguity.

Author: Patrick Wendell <patrick@databricks.com>

Closes #5620 from pwendell/cleanup and squashes the following commits:

8d8f44f [Patrick Wendell] [Minor] Comment improvements in ExternalSorter.

Added docs for rpc configurations and also fixed two places that should have been fixed in #5595.

Author: zsxwing <zsxwing@gmail.com>

Closes #5607 from zsxwing/SPARK-6490-docs and squashes the following commits:

25a6736 [zsxwing] Increase the default timeout to 120s
6e37c30 [zsxwing] Update docs
5577540 [zsxwing] Use spark.network.timeout as the default timeout if it presents
4f07174 [zsxwing] Fix unit tests
1c2cf26 [zsxwing] Add docs for rpc configurations

Cleans up the pull request title in the merge script to follow conventions outlined in the wiki under Contributing Code.
https://cwiki.apache.org/confluence/display/SPARK/Contributing+to+Spark#ContributingtoSpark-ContributingCode

[MODULE] SPARK-XXXX: Description

Author: texasmichelle <texasmichelle@gmail.com>

Closes #5149 from texasmichelle/master and squashes the following commits:

9b6b0a7 [texasmichelle] resolved variable scope issue
7d5fa20 [texasmichelle] only prompt if title has been modified
8c195bb [texasmichelle] removed erroneous line
4f1ed46 [texasmichelle] Deque removal, logic simplifications, & prompt user to pick a title (orig or modified)
df73f6a [texasmichelle] reworked regex's to enforce brackets around JIRA ref
43b5aed [texasmichelle] Merge remote-tracking branch 'apache/master'
25229c6 [texasmichelle] Merge remote-tracking branch 'apache/master'
aa20a6e [texasmichelle] Move code into main() and add doctest for new text parsing method
48520ba [texasmichelle] SPARK-1684: Corrected import statement
042099d [texasmichelle] SPARK-1684 Merge script should standardize SPARK-XXX prefix
8f4a7d1 [texasmichelle] SPARK-1684 Merge script should standardize SPARK-XXX prefix

This PR try to speed up some python tests:

```
tests.py                       144s -> 103s      -41s
mllib/classification.py         24s -> 17s        -7s
mllib/regression.py             27s -> 15s       -12s
mllib/tree.py                   27s -> 13s       -14s
mllib/tests.py                  64s -> 31s       -33s
streaming/tests.py             185s -> 84s      -101s
```
Considering python3, the total saving will be 558s (almost 10 minutes) (core, and streaming run three times, mllib runs twice).

During testing, it will show used time for each test file:
```
Run core tests ...
Running test: pyspark/rdd.py ... ok (22s)
Running test: pyspark/context.py ... ok (16s)
Running test: pyspark/conf.py ... ok (4s)
Running test: pyspark/broadcast.py ... ok (4s)
Running test: pyspark/accumulators.py ... ok (4s)
Running test: pyspark/serializers.py ... ok (6s)
Running test: pyspark/profiler.py ... ok (5s)
Running test: pyspark/shuffle.py ... ok (1s)
Running test: pyspark/tests.py ... ok (103s)   144s
```

Author: Reynold Xin <rxin@databricks.com>
Author: Xiangrui Meng <meng@databricks.com>

Closes #5605 from rxin/python-tests-speed and squashes the following commits:

d08542d [Reynold Xin] Merge pull request #14 from mengxr/SPARK-6953
89321ee [Xiangrui Meng] fix seed in tests
3ad2387 [Reynold Xin] Merge pull request #5427 from davies/python_tests

This change adds some new utility code to handle shutdown hooks in
Spark. The main goal is to take advantage of Hadoop 2.x's API for
shutdown hooks, which allows Spark to register a hook that will
run before the one that cleans up HDFS clients, and thus avoids
some races that would cause exceptions to show up and other issues
such as failure to properly close event logs.

Unfortunately, Hadoop 1.x does not have such APIs, so in that case
correctness is still left to chance.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #5560 from vanzin/SPARK-6014 and squashes the following commits:

edfafb1 [Marcelo Vanzin] Better scaladoc.
fcaeedd [Marcelo Vanzin] Merge branch 'master' into SPARK-6014
e7039dc [Marcelo Vanzin] [SPARK-6014] [core] Revamp Spark shutdown hooks, fix shutdown races.

Starting with version 0.21.0, Apache Mesos is very noisy if the filter parameter refuse_seconds is set to an invalid value like `-1`.
I have seen systems with millions of log lines like
```
W0420 18:00:48.773059 32352 hierarchical_allocator_process.hpp:589] Using the default value of 'refuse_seconds' to create the refused resources filter because the input value is negative
```
in the Mesos master INFO and WARNING log files.
Therefore the CoarseMesosSchedulerBackend should set the default value for refuse seconds (i.e. 5 seconds) directly.
This is no problem for the fine-grained MesosSchedulerBackend, as it uses the value 1 second for this parameter.

Author: mweindel <m.weindel@usu-software.de>

Closes #5597 from MartinWeindel/master and squashes the following commits:

2f99ffd [mweindel] Avoid warning message about invalid refuse_seconds value in Mesos >=0.21.

add missing comma and space

Author: Alain <aihe@usc.edu>

Closes #5621 from AiHe/tree-node-issue and squashes the following commits:

159a7bb [Alain] [Minor][MLLIB] Fix a minor formatting bug in toString methods in Node.scala

(cherry picked from commit 4508f01890a723f80d631424ff8eda166a13a727)
Signed-off-by: Xiangrui Meng <meng@databricks.com>

SchemaRDD works with ALS.train in 1.2, so we should continue support DataFrames for compatibility. coderxiang

Author: Xiangrui Meng <meng@databricks.com>

Closes #5619 from mengxr/SPARK-7036 and squashes the following commits:

dfcaf5a [Xiangrui Meng] ALS.train should support DataFrames in PySpark

1. Use blas calls to find the dot product between two vectors.
2. Prevent re-computing the L2 norm of the given vector for each word in model.

Author: MechCoder <manojkumarsivaraj334@gmail.com>

Closes #5467 from MechCoder/spark-6065 and squashes the following commits:

dd0b0b2 [MechCoder] Preallocate wordVectors
ffc9240 [MechCoder] Minor
6b74c81 [MechCoder] Switch back to native blas calls
da1642d [MechCoder] Explicit types and indexing
64575b0 [MechCoder] Save indexedmap and a wordvecmat instead of matrix
fbe0108 [MechCoder] Made the following changes 1. Calculate norms during initialization. 2. Use Blas calls from linalg.blas
1350cf3 [MechCoder] [SPARK-6065] Optimize word2vec.findSynonynms using blas calls

The default java options make the call to GenerateMIMAIgnore take
forever to run since it's gc'ing all the time. Improve things by
setting the perm gen size / max heap size to larger values.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #5615 from vanzin/gen-mima-fix and squashes the following commits:

f44e921 [Marcelo Vanzin] [minor] [build] Set java options when generating mima ignores.

This patch modifies several shuffle-related code paths to share and re-use SerializerInstances instead of creating new ones.  Some serializers, such as KryoSerializer or SqlSerializer, can be fairly expensive to create or may consume moderate amounts of memory, so it's probably best to avoid unnecessary serializer creation in hot code paths.

The key change in this patch is modifying `getDiskWriter()` / `DiskBlockObjectWriter` to accept `SerializerInstance`s instead of `Serializer`s (which are factories for instances).  This allows the disk writer's creator to decide whether the serializer instance can be shared or re-used.

The rest of the patch modifies several write and read paths to use shared serializers.  One big win is in `ShuffleBlockFetcherIterator`, where we used to create a new serializer per received block.  Similarly, the shuffle write path used to create a new serializer per file even though in many cases only a single thread would be writing to a file at a time.

I made a small serializer reuse optimization in CoarseGrainedExecutorBackend as well, since it seemed like a small and obvious improvement.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #5606 from JoshRosen/SPARK-3386 and squashes the following commits:

f661ce7 [Josh Rosen] Remove thread local; add comment instead
64f8398 [Josh Rosen] Use ThreadLocal for serializer instance in CoarseGrainedExecutorBackend
aeb680e [Josh Rosen] [SPARK-3386] Reuse SerializerInstance in shuffle code paths

It's a bug while do query like:
```sql
select d from (select explode(array(1,1)) d from src limit 1) t
```
And it will throws exception like:
```
org.apache.spark.sql.AnalysisException: cannot resolve 'd' given input columns _c0; line 1 pos 7
at org.apache.spark.sql.catalyst.analysis.package$AnalysisErrorAt.failAnalysis(package.scala:42)
at org.apache.spark.sql.catalyst.analysis.CheckAnalysis$$anonfun$apply$3$$anonfun$apply$1.applyOrElse(CheckAnalysis.scala:48)
at org.apache.spark.sql.catalyst.analysis.CheckAnalysis$$anonfun$apply$3$$anonfun$apply$1.applyOrElse(CheckAnalysis.scala:45)
at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$transformUp$1.apply(TreeNode.scala:250)
at org.apache.spark.sql.catalyst.trees.TreeNode$$anonfun$transformUp$1.apply(TreeNode.scala:250)
at org.apache.spark.sql.catalyst.trees.CurrentOrigin$.withOrigin(TreeNode.scala:50)
at org.apache.spark.sql.catalyst.trees.TreeNode.transformUp(TreeNode.scala:249)
at org.apache.spark.sql.catalyst.plans.QueryPlan.org$apache$spark$sql$catalyst$plans$QueryPlan$$transformExpressionUp$1(QueryPlan.scala:103)
at org.apache.spark.sql.catalyst.plans.QueryPlan$$anonfun$2$$anonfun$apply$2.apply(QueryPlan.scala:117)
at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
at scala.collection.mutable.ResizableArray$class.foreach(ResizableArray.scala:59)
at scala.collection.mutable.ArrayBuffer.foreach(ArrayBuffer.scala:47)
at scala.collection.TraversableLike$class.map(TraversableLike.scala:244)
at scala.collection.AbstractTraversable.map(Traversable.scala:105)
at org.apache.spark.sql.catalyst.plans.QueryPlan$$anonfun$2.apply(QueryPlan.scala:116)
at scala.collection.Iterator$$anon$11.next(Iterator.scala:328)
```

To solve the bug, it requires code refactoring for UDTF
The major changes are about:
* Simplifying the UDTF development, UDTF will manage the output attribute names any more, instead, the `logical.Generate` will handle that properly.
* UDTF will be asked for the output schema (data types) during the logical plan analyzing.

Author: Cheng Hao <hao.cheng@intel.com>

Closes #4602 from chenghao-intel/explode_bug and squashes the following commits:

c2a5132 [Cheng Hao] add back resolved for Alias
556e982 [Cheng Hao] revert the unncessary change
002c361 [Cheng Hao] change the rule of resolved for Generate
04ae500 [Cheng Hao] add qualifier only for generator output
5ee5d2c [Cheng Hao] prepend the new qualifier
d2e8b43 [Cheng Hao] Update the code as feedback
ca5e7f4 [Cheng Hao] shrink the commits

liancheng mengxr this is similar to #5146.

Author: Punya Biswal <pbiswal@palantir.com>

Closes #5578 from punya/feature/SPARK-6996 and squashes the following commits:

d56c3e0 [Punya Biswal] Fix imports
c7e308b [Punya Biswal] Support java iterable types in POJOs
5e00685 [Punya Biswal] Support map types in java beans

https://issues.apache.org/jira/browse/SPARK-6969

Author: Yin Huai <yhuai@databricks.com>

Closes #5583 from yhuai/refreshTableRefreshDataCache and squashes the following commits:

1e5142b [Yin Huai] Add todo.
92b2498 [Yin Huai] Minor updates.
367df92 [Yin Huai] Recache data in the command of REFRESH TABLE.

[SQL][minor] make it more clear that we only need to re-throw GetField exception for UnresolvedAttribute

For `GetField` outside `UnresolvedAttribute`, we will throw exception in `Analyzer`.

Author: Wenchen Fan <cloud0fan@outlook.com>

Closes #5588 from cloud-fan/tmp and squashes the following commits:

7ac74d2 [Wenchen Fan] small refactor

It looked weird that up to now there was no way in Spark's Scala API to access fields of `DataFrame/sql.Row` by name, only by their index.

This tries to solve this issue.

Author: vidmantas zemleris <vidmantas@vinted.com>

Closes #5573 from vidma/features/row-with-named-fields and squashes the following commits:

6145ae3 [vidmantas zemleris] [SPARK-6994][SQL] Allow to fetch field values by name on Row
9564ebb [vidmantas zemleris] [SPARK-6994][SQL] Add fieldIndex to schema (StructType)

[SPARK-7011] Build(compilation) fails with scala 2.11 option, because a protected[sql] type is accessed in ml package.

[This](https://github.com/apache/spark/blob/master/mllib/src/main/scala/org/apache/spark/ml/feature/VectorAssembler.scala#L58) is where it is used and fails compilations at.

Author: Prashant Sharma <prashant.s@imaginea.com>

Closes #5593 from ScrapCodes/SPARK-7011/build-fix and squashes the following commits:

e6d57a3 [Prashant Sharma] [SPARK-7011] Build fails with scala 2.11 option, because a protected[sql] type is accessed in ml package.

Since sparse matrices now support a isTransposed flag for row major data, DenseMatrices should do the same.

Author: MechCoder <manojkumarsivaraj334@gmail.com>

Closes #5455 from MechCoder/spark-6845 and squashes the following commits:

525c370 [MechCoder] minor
004a37f [MechCoder] Cast boolean to int
151f3b6 [MechCoder] [WIP] Add isTransposed to pickle DenseMatrix
cc0b90a [MechCoder] [SPARK-6845] Add isTranposed flag to DenseMatrix

SPARK-3276 Added a new configuration parameter ``spark.streaming.minRememberDuration``, with a default value of 1 minute.

So that when a Spark Streaming application is started, an arbitrary number of minutes can be taken as threshold for remembering.

Author: emres <emre.sevinc@gmail.com>

Closes #5438 from emres/SPARK-3276 and squashes the following commits:

766f938 [emres] SPARK-3276 Switched to using newly added getTimeAsSeconds method.
affee1d [emres] SPARK-3276 Changed the property name and variable name for minRememberDuration
c9d58ca [emres] SPARK-3276 Minor code re-formatting.
1c53ba9 [emres] SPARK-3276 Started to use ssc.conf rather than ssc.sparkContext.getConf,  and also getLong method directly.
bfe0acb [emres] SPARK-3276 Moved the minRememberDurationMin to the class
daccc82 [emres] SPARK-3276 Changed the property name to reflect the unit of value and reduced number of fields.
43cc1ce [emres] SPARK-3276 Added a new configuration parameter spark.streaming.minRemember duration, with a default value of 1 minute.

CoGroupPartition, part of CoGroupedRDD, includes references to each RDD that the CoGroupedRDD narrowly depends on, and a reference to the ShuffleHandle. The partition is serialized separately from the RDD, so when the RDD and partition arrive on the worker, the references in the partition and in the RDD no longer point to the same object.

This is a relatively minor performance issue (the closure can be 2x larger than it needs to be because the rdds and partitions are serialized twice; see numbers below) but is more annoying as a developer issue (this is where I ran into): if any state is stored in the RDD or ShuffleHandle on the worker side, subtle bugs can appear due to the fact that the references to the RDD / ShuffleHandle in the RDD and in the partition point to separate objects. I'm not sure if this is enough of a potential future problem to fix this old and central part of the code, so hoping to get input from others here.

I did some simple experiments to see how much this effects closure size. For this example:
$ val a = sc.parallelize(1 to 10).map((_, 1))
$ val b = sc.parallelize(1 to 2).map(x => (x, 2*x))
$ a.cogroup(b).collect()
the closure was 1902 bytes with current Spark, and 1129 bytes after my change. The difference comes from eliminating duplicate serialization of the shuffle handle.

For this example:
$ val sortedA = a.sortByKey()
$ val sortedB = b.sortByKey()
$ sortedA.cogroup(sortedB).collect()
the closure was 3491 bytes with current Spark, and 1333 bytes after my change. Here, the difference comes from eliminating duplicate serialization of the two RDDs for the narrow dependencies.

The ShuffleHandle includes the ShuffleDependency, so this difference will get larger if a ShuffleDependency includes a serializer, a key ordering, or an aggregator (all set to None by default). It would also get bigger for a big RDD -- although I can't think of any examples where the RDD object gets large.  The difference is not affected by the size of the function the user specifies, which (based on my understanding) is typically the source of large task closures.

Author: Kay Ousterhout <kayousterhout@gmail.com>

Closes #4145 from kayousterhout/SPARK-5360 and squashes the following commits:

85156c3 [Kay Ousterhout] Better comment the narrowDeps parameter
cff0209 [Kay Ousterhout] Fixed spelling issue
658e1af [Kay Ousterhout] [SPARK-5360] Eliminate duplicate objects in serialized CoGroupedRDD

A simple truncation in integer division (on rates over 1000 messages / second) causes the existing implementation to sleep for 0 milliseconds, then call itself recursively; this causes what is essentially an infinite recursion, since the base case of the calculated amount of time having elapsed can't be reached before available stack space is exhausted. A fix to this truncation error is included in this patch.

However, even with the defect patched, the accuracy of the existing implementation is abysmal (the error bounds of the original test were effectively [-30%, +10%], although this fact was obscured by hard-coded error margins); as such, when the error bounds were tightened down to [-5%, +5%], the existing implementation failed to meet the new, tightened, requirements. Therefore, an industry-vetted solution (from Guava) was used to get the adapted tests to pass.

Author: David McGuire <david.mcguire2@nike.com>

Closes #5559 from dmcguire81/master and squashes the following commits:

d29d2e0 [David McGuire] Back out to +/-5% error margins, for flexibility in timing
8be6934 [David McGuire] Fix spacing per code review
90e98b9 [David McGuire] Address scalastyle errors
29011bd [David McGuire] Further ratchet down the error margins
b33b796 [David McGuire] Eliminate dependency on even distribution by BlockGenerator
8f2934b [David McGuire] Remove arbitrary thread timing / cooperation code
70ee310 [David McGuire] Use Thread.yield(), since Thread.sleep(0) is system-dependent
82ee46d [David McGuire] Replace guard clause with nested conditional
2794717 [David McGuire] Replace the RateLimiter with the Guava implementation
38f3ca8 [David McGuire] Ratchet down the error rate to +/- 5%; tests fail
24b1bc0 [David McGuire] Fix truncation in integer division causing infinite recursion
d6e1079 [David McGuire] Stack overflow error in RateLimiter on rates over 1000/s

Model import/export for IsotonicRegression

Author: Yanbo Liang <ybliang8@gmail.com>

Closes #5270 from yanboliang/spark-5990 and squashes the following commits:

872028d [Yanbo Liang] fix code style
f80ec1b [Yanbo Liang] address comments
49600cc [Yanbo Liang] address comments
429ff7d [Yanbo Liang] store each interval as a record
2b2f5a1 [Yanbo Liang] Model import/export for IsotonicRegression

This PR enable auto_convert in JavaGateway, then we could register a converter for a given types, for example, date and datetime.

There are two bugs related to auto_convert, see [1] and [2], we workaround it in this PR.

[1]  https://github.com/bartdag/py4j/issues/160
[2] https://github.com/bartdag/py4j/issues/161

cc rxin JoshRosen

Author: Davies Liu <davies@databricks.com>

Closes #5570 from davies/py4j_date and squashes the following commits:

eb4fa53 [Davies Liu] fix tests in python 3
d17d634 [Davies Liu] rollback changes in mllib
2e7566d [Davies Liu] convert tuple into ArrayList
ceb3779 [Davies Liu] Update rdd.py
3c373f3 [Davies Liu] support date and datetime by auto_convert
cb094ff [Davies Liu] enable auto convert

Deprecated `spark.akka.num.retries`, `spark.akka.retry.wait`, `spark.akka.askTimeout`,  `spark.akka.lookupTimeout`, and added `spark.rpc.num.retries`, `spark.rpc.retry.wait`, `spark.rpc.askTimeout`, `spark.rpc.lookupTimeout`.

Author: zsxwing <zsxwing@gmail.com>

Closes #5595 from zsxwing/SPARK-6490 and squashes the following commits:

e0d80a9 [zsxwing] Use getTimeAsMs and getTimeAsSeconds and other minor fixes
31dbe69 [zsxwing] Add spark.rpc.* and deprecate spark.akka.*

JIRA https://issues.apache.org/jira/browse/SPARK-6635

Author: Liang-Chi Hsieh <viirya@gmail.com>

Closes #5541 from viirya/replace_with_column and squashes the following commits:

b539c7b [Liang-Chi Hsieh] For comment.
72f35b1 [Liang-Chi Hsieh] DataFrame.withColumn can replace original column with identical column name.

JIRA: https://issues.apache.org/jira/browse/SPARK-6368

Author: Yin Huai <yhuai@databricks.com>

Closes #5497 from yhuai/serializer2 and squashes the following commits:

da562c5 [Yin Huai] Merge remote-tracking branch 'upstream/master' into serializer2
50e0c3d [Yin Huai] When no filed is emitted to shuffle, use SparkSqlSerializer for now.
9f1ed92 [Yin Huai] Merge remote-tracking branch 'upstream/master' into serializer2
6d07678 [Yin Huai] Address comments.
4273b8c [Yin Huai] Enabled SparkSqlSerializer2.
09e587a [Yin Huai] Remove TODO.
791b96a [Yin Huai] Use UTF8String.
60a1487 [Yin Huai] Merge remote-tracking branch 'upstream/master' into serializer2
3e09655 [Yin Huai] Use getAs for Date column.
43b9fb4 [Yin Huai] Test.
8297732 [Yin Huai] Fix test.
c9373c8 [Yin Huai] Support DecimalType.
2379eeb [Yin Huai] ASF header.
39704ab [Yin Huai] Specialized serializer for Exchange.

The commit message is pretty self-explanatory.

Author: BenFradet <benjamin.fradet@gmail.com>

Closes #5600 from BenFradet/master and squashes the following commits:

108492d [BenFradet] [doc][streaming] Fixed broken link in mllib section

The contribution is my original work. I license the work to the project under the project's open source license.

Small typo in the programming guide.

Author: Eric Chiang <eric.chiang.m@gmail.com>

Closes #5599 from ericchiang/docs-typo and squashes the following commits:

1177942 [Eric Chiang] fixed doc

It should load from `testInput` instead of `input` for test data.

Author: Liang-Chi Hsieh <viirya@gmail.com>

Closes #5594 from viirya/use_testinput and squashes the following commits:

5e8b174 [Liang-Chi Hsieh] Fix style.
b60b475 [Liang-Chi Hsieh] Use testInput.

Author: Elisey Zanko <elisey.zanko@gmail.com>

Closes #5361 from 31z4/spark-6661 and squashes the following commits:

73c5d79 [Elisey Zanko] Python type errors should print type, not object

[SPARK-7003] Improve reliability of connection failure detection between Netty block transfer service endpoints

Currently we rely on the assumption that an exception will be raised and the channel closed if two endpoints cannot communicate over a Netty TCP channel. However, this guarantee does not hold in all network environments, and [SPARK-6962](https://issues.apache.org/jira/browse/SPARK-6962) seems to point to a case where only the server side of the connection detected a fault.

This patch improves robustness of fetch/rpc requests by having an explicit timeout in the transport layer which closes the connection if there is a period of inactivity while there are outstanding requests.

NB: This patch is actually only around 50 lines added if you exclude the testing-related code.

Author: Aaron Davidson <aaron@databricks.com>

Closes #5584 from aarondav/timeout and squashes the following commits:

8699680 [Aaron Davidson] Address Reynold's comments
37ce656 [Aaron Davidson] [SPARK-7003] Improve reliability of connection failure detection between Netty block transfer service endpoints

The current implementation call the default constructor of mllib.feature.StandarScaler without the possibility to specify withMean or withStd options.

Author: jrabary <Jaonary@gmail.com>

Closes #4704 from jrabary/master and squashes the following commits:

fae8568 [jrabary] style fix
8896b0e [jrabary] Comments fix
ef96d73 [jrabary] style fix
8e52607 [jrabary] style fix
edd9d48 [jrabary] Fix default param initialization
17e1a76 [jrabary] Fix default param initialization
298f405 [jrabary] Typo fix
45ed914 [jrabary] Add withMean and withStd params to StandarScaler

* Fix the page title in Isotonic regression documents (Naive Bayes -> Isotonic regression)
* Add a newline character at the end of the file

Author: dobashim <dobashim@oss.nttdata.co.jp>

Closes #5581 from dobashim/master and squashes the following commits:

d54a041 [dobashim] Fix typo of the page title in Isotonic regression documents

Title says it all.

cc rxin tdas

Author: zsxwing <zsxwing@gmail.com>

Closes #5554 from zsxwing/SPARK-6979 and squashes the following commits:

5304350 [zsxwing] Fix NotSerializableException
e9d3479 [zsxwing] Add blank lines
633e279 [zsxwing] Fix NotSerializableException
e496ace [zsxwing] Replace JobGenerator.eventActor with EventLoop
ec6ec58 [zsxwing] Fix the import order
ce0fa73 [zsxwing] Replace JobScheduler.eventActor with EventLoop

A subtask of [SPARK-5293](https://issues.apache.org/jira/browse/SPARK-5293)

Author: zsxwing <zsxwing@gmail.com>

Closes #5557 from zsxwing/SPARK-6983 and squashes the following commits:

e777e9f [zsxwing] Update ReceiverTrackerActor to use the new Rpc interface

If `StreamingKMeans` is not `Serializable`, we cannot do checkpoint for applications that using `StreamingKMeans`. So we should make it `Serializable`.

Author: zsxwing <zsxwing@gmail.com>

Closes #5582 from zsxwing/SPARK-6998 and squashes the following commits:

67c2a14 [zsxwing] Make StreamingKMeans 'Serializable'

cc andrewor14

Author: GuoQiang Li <witgo@qq.com>

Closes #5548 from witgo/SPARK-6963 and squashes the following commits:

964aea7 [GuoQiang Li] review commits
b08b3c9 [GuoQiang Li] Flaky test: o.a.s.ContextCleanerSuite automatically cleanup checkpoint

The default method will use Guava's Ordering instead of
java.util.Comparator.naturalOrder() because it's not available
in Java 7, only in Java 8.

Author: Olivier Girardot <o.girardot@lateral-thoughts.com>

Closes #5571 from ogirardot/master and squashes the following commits:

7fe2e9e [Olivier Girardot] SPARK-6993 : Add default min, max methods for JavaDoubleRDD