Author: Michael Armbrust <michael@databricks.com>

Closes #4642 from marmbrus/docs and squashes the following commits:

d291c34 [Michael Armbrust] python tests
9be66e3 [Michael Armbrust] comments
d56afc2 [Michael Armbrust] fix style
f004747 [Michael Armbrust] fix build
c4a907b [Michael Armbrust] fix tests
42e2b73 [Michael Armbrust] [SQL] Documentation / API Clean-up.

Added a bunch of tags.

Also changed parquetFile to take varargs rather than a string followed by varargs.

Author: Reynold Xin <rxin@databricks.com>

Closes #4636 from rxin/df-doc and squashes the following commits:

651f80c [Reynold Xin] Fixed parquetFile in PySpark.
8dc3024 [Reynold Xin] [SQL] Various DataFrame doc changes.

- The old implicit would convert RDDs directly to DataFrames, and that added too many methods.
- toDataFrame -> toDF
- Dsl -> functions
- implicits moved into SQLContext.implicits
- addColumn -> withColumn
- renameColumn -> withColumnRenamed

Python changes:
- toDataFrame -> toDF
- Dsl -> functions package
- addColumn -> withColumn
- renameColumn -> withColumnRenamed
- add toDF functions to RDD on SQLContext init
- add flatMap to DataFrame

Author: Reynold Xin <rxin@databricks.com>
Author: Davies Liu <davies@databricks.com>

Closes #4556 from rxin/SPARK-5752 and squashes the following commits:

5ef9910 [Reynold Xin] More fix
61d3fca [Reynold Xin] Merge branch 'df5' of github.com:davies/spark into SPARK-5752
ff5832c [Reynold Xin] Fix python
749c675 [Reynold Xin] count(*) fixes.
5806df0 [Reynold Xin] Fix build break again.
d941f3d [Reynold Xin] Fixed explode compilation break.
fe1267a [Davies Liu] flatMap
c4afb8e [Reynold Xin] style
d9de47f [Davies Liu] add comment
b783994 [Davies Liu] add comment for toDF
e2154e5 [Davies Liu] schema() -> schema
3a1004f [Davies Liu] Dsl -> functions, toDF()
fb256af [Reynold Xin] - toDataFrame -> toDF - Dsl -> functions - implicits moved into SQLContext.implicits - addColumn -> withColumn - renameColumn -> withColumnRenamed
0dd74eb [Reynold Xin] [SPARK-5752][SQL] Don't implicitly convert RDDs directly to DataFrames
97dd47c [Davies Liu] fix mistake
6168f74 [Davies Liu] fix test
1fc0199 [Davies Liu] fix test
a075cd5 [Davies Liu] clean up, toPandas
663d314 [Davies Liu] add test for agg('*')
9e214d5 [Reynold Xin] count(*) fixes.
1ed7136 [Reynold Xin] Fix build break again.
921b2e3 [Reynold Xin] Fixed explode compilation break.
14698d4 [Davies Liu] flatMap
ba3e12d [Reynold Xin] style
d08c92d [Davies Liu] add comment
5c8b524 [Davies Liu] add comment for toDF
a4e5e66 [Davies Liu] schema() -> schema
d377fc9 [Davies Liu] Dsl -> functions, toDF()
6b3086c [Reynold Xin] - toDataFrame -> toDF - Dsl -> functions - implicits moved into SQLContext.implicits - addColumn -> withColumn - renameColumn -> withColumnRenamed
807e8b1 [Reynold Xin] [SPARK-5752][SQL] Don't implicitly convert RDDs directly to DataFrames

https://issues.apache.org/jira/browse/SPARK-3299

Author: Yin Huai <yhuai@databricks.com>

Closes #4547 from yhuai/tables and squashes the following commits:

6c8f92e [Yin Huai] Add tableNames.
acbb281 [Yin Huai] Update Python test.
7793dcb [Yin Huai] Fix scala test.
572870d [Yin Huai] Address comments.
aba2e88 [Yin Huai] Format.
12c86df [Yin Huai] Add tables() to SQLContext to return a DataFrame containing existing tables.

1. DataFrame.renameColumn

2. DataFrame.show() and _repr_

3. Use simpleString() rather than jsonValue in DataFrame.dtypes

4. createDataFrame from local Python data, including pandas.DataFrame

Author: Davies Liu <davies@databricks.com>

Closes #4528 from davies/df3 and squashes the following commits:

014acea [Davies Liu] fix typo
6ba526e [Davies Liu] fix tests
46f5f95 [Davies Liu] address comments
6cbc154 [Davies Liu] dataframe.show() and improve dtypes
6f94f25 [Davies Liu] create DataFrame from local Python data

Deprecate inferSchema() and applySchema(), use createDataFrame() instead, which could take an optional `schema` to create an DataFrame from an RDD. The `schema` could be StructType or list of names of columns.

Author: Davies Liu <davies@databricks.com>

Closes #4498 from davies/create and squashes the following commits:

08469c1 [Davies Liu] remove Scala/Java API for now
c80a7a9 [Davies Liu] fix hive test
d1bd8f2 [Davies Liu] cleanup applySchema
9526e97 [Davies Liu] createDataFrame from RDD with columns

https://issues.apache.org/jira/browse/SPARK-5658

Author: Yin Huai <yhuai@databricks.com>

This patch had conflicts when merged, resolved by
Committer: Michael Armbrust <michael@databricks.com>

Closes #4446 from yhuai/writeSupportFollowup and squashes the following commits:

f3a96f7 [Yin Huai] davies's comments.
225ff71 [Yin Huai] Use Scala TestHiveContext to initialize the Python HiveContext in Python tests.
2306f93 [Yin Huai] Style.
2091fcd [Yin Huai] Merge remote-tracking branch 'upstream/master' into writeSupportFollowup
537e28f [Yin Huai] Correctly clean up temp data.
ae4649e [Yin Huai] Fix Python test.
609129c [Yin Huai] Doc format.
92b6659 [Yin Huai] Python doc and other minor updates.
cbc717f [Yin Huai] Rename dataSourceName to source.
d1c12d3 [Yin Huai] No need to delete the duplicate rule since it has been removed in master.
22cfa70 [Yin Huai] Merge remote-tracking branch 'upstream/master' into writeSupportFollowup
d91ecb8 [Yin Huai] Fix test.
4c76d78 [Yin Huai] Simplify APIs.
3abc215 [Yin Huai] Merge remote-tracking branch 'upstream/master' into writeSupportFollowup
0832ce4 [Yin Huai] Fix test.
98e7cdb [Yin Huai] Python style.
2bf44ef [Yin Huai] Python APIs.
c204967 [Yin Huai] Format
a10223d [Yin Huai] Merge remote-tracking branch 'upstream/master' into writeSupportFollowup
9ff97d8 [Yin Huai] Add SaveMode to saveAsTable.
9b6e570 [Yin Huai] Update doc.
c2be775 [Yin Huai] Merge remote-tracking branch 'upstream/master' into writeSupportFollowup
99950a2 [Yin Huai] Use Java enum for SaveMode.
4679665 [Yin Huai] Remove duplicate rule.
77d89dc [Yin Huai] Update doc.
e04d908 [Yin Huai] Move import and add (Scala-specific) to scala APIs.
cf5703d [Yin Huai] Add checkAnswer to Java tests.
7db95ff [Yin Huai] Merge remote-tracking branch 'upstream/master' into writeSupportFollowup
6dfd386 [Yin Huai] Add java test.
f2f33ef [Yin Huai] Fix test.
e702386 [Yin Huai] Apache header.
b1e9b1b [Yin Huai] Format.
ed4e1b4 [Yin Huai] Merge remote-tracking branch 'upstream/master' into writeSupportFollowup
af9e9b3 [Yin Huai] DDL and write support API followup.
2a6213a [Yin Huai] Update API names.
e6a0b77 [Yin Huai] Update test.
43bae01 [Yin Huai] Remove createTable from HiveContext.
5ffc372 [Yin Huai] Add more load APIs to SQLContext.
5390743 [Yin Huai] Add more save APIs to DataFrame.

All the DataTypes moved into pyspark.sql.types

The changes can be tracked by `--find-copies-harder -M25`
```
davieslocalhost:~/work/spark/python$ git diff --find-copies-harder -M25 --numstat master..
2       5       python/docs/pyspark.ml.rst
0       3       python/docs/pyspark.mllib.rst
10      2       python/docs/pyspark.sql.rst
1       1       python/pyspark/mllib/linalg.py
21      14      python/pyspark/{mllib => sql}/__init__.py
14      2108    python/pyspark/{sql.py => sql/context.py}
10      1772    python/pyspark/{sql.py => sql/dataframe.py}
7       6       python/pyspark/{sql_tests.py => sql/tests.py}
8       1465    python/pyspark/{sql.py => sql/types.py}
4       2       python/run-tests
1       1       sql/core/src/main/scala/org/apache/spark/sql/test/ExamplePointUDT.scala
```

Also `git blame -C -C python/pyspark/sql/context.py` to track the history.

Author: Davies Liu <davies@databricks.com>

Closes #4479 from davies/sql and squashes the following commits:

1b5f0a5 [Davies Liu] Merge branch 'master' of github.com:apache/spark into sql
2b2b983 [Davies Liu] restructure pyspark.sql