Use different Hadoop version for YARN artifacts.

This uses a seperate Hadoop version for YARN artifact. This means when people link against
spark-yarn, things will resolve correctly.

Changed localProperties to use ThreadLocal (not DynamicVariable).

Updated Spark on Mesos documentation.

The fact that DynamicVariable uses an InheritableThreadLocal
can cause problems where the properties end up being shared
across threads in certain circumstances.

Add explicit jets3t dependency, which is excluded in hadoop-client

Change default port number from 3030 to 4030.

SPARK-894 - Not all WebUI fields delivered VIA JSON

fix run-example script

Fix HDFS access bug with assembly build.

Due to this change in HDFS:
https://issues.apache.org/jira/browse/HADOOP-7549

there is a bug when using the new assembly builds. The symptom is that any HDFS access
results in an exception saying "No filesystem for scheme 'hdfs'". This adds a merge
strategy in the assembly build which fixes the problem.

Document libgfortran dependency for MLBase

Get rid of / improve ugly NPE when Utils.deleteRecursively() fails

Fix copy issue in https://github.com/mesos/spark/pull/899

Add better docs for coalesce.

listFiles() could return null if the I/O fails, and this currently results in an ugly NPE which is hard to diagnose.

Add metrics-ganglia to core pom file

Adding Manen dependency for Ganglia

Fix hash bug