SPARK-1898: In deploy.yarn.Client, use YarnClient not YarnClientImpl

https://issues.apache.org/jira/browse/SPARK-1898

Author: Colin Patrick McCabe <cmccabe@cloudera.com>

Closes #850 from cmccabe/master and squashes the following commits:

d66eddc [Colin Patrick McCabe] SPARK-1898: In deploy.yarn.Client, use YarnClient rather than YarnClientImpl
SPARK-1628: Add missing hashCode methods in Partitioner subclasses

JIRA: https://issues.apache.org/jira/browse/SPARK-1628

Added `hashCode` in HashPartitioner, RangePartitioner, PythonPartitioner and PageRankUtils.CustomPartitioner.

Author: zsxwing <zsxwing@gmail.com>

Closes #549 from zsxwing/SPARK-1628 and squashes the following commits:

2620936 [zsxwing] SPARK-1628: Add missing hashCode methods in Partitioner subclasses
Update run-example

Old code can only be ran under spark_home and use "bin/run-example".
 Error "./run-example: line 55: ./bin/spark-submit: No such file or directory" appears when running in other place. So change this

Author: maji2014 <maji3@asiainfo-linkage.com>

Closes #1011 from maji2014/master and squashes the following commits:

2cc1af6 [maji2014] Update run-example

Closes #988.
SPARK-1628 follow up: Improve RangePartitioner's documentation.

Adding a paragraph clarifying a weird behavior in RangePartitioner.

See also #549.

Author: Reynold Xin <rxin@apache.org>

Closes #1012 from rxin/partitioner-doc and squashes the following commits:

6f0109e [Reynold Xin] SPARK-1628 follow up: Improve RangePartitioner's documentation.
[SPARK-2067] use relative path for Spark logo in UI

Author: Neville Li <neville@spotify.com>

Closes #1006 from nevillelyh/gh/SPARK-2067 and squashes the following commits:

9ee64cf [Neville Li] [SPARK-2067] use relative path for Spark logo in UI
Grammar: read -> reads

Author: Andrew Ash <andrew@andrewash.com>

Closes #1016 from ash211/patch-6 and squashes the following commits:

e3865c8 [Andrew Ash] Grammar: read -> reads
[SPARK-1308] Add getNumPartitions to pyspark RDD

Add getNumPartitions to pyspark RDD to provide an intuitive way to get number of partitions in RDD like we can do in scala today.

Author: Syed Hashmi <shashmi@cloudera.com>

Closes #995 from syedhashmi/master and squashes the following commits:

de0ed5e [Syed Hashmi] [SPARK-1308] Add getNumPartitions to pyspark RDD