SPARK-1813. Add a utility to SparkConf that makes using Kryo really easy

Author: Sandy Ryza <sandy@cloudera.com>

Closes #789 from sryza/sandy-spark-1813 and squashes the following commits:

48b05e9 [Sandy Ryza] Simplify
b824932 [Sandy Ryza] Allow both spark.kryo.classesToRegister and spark.kryo.registrator at the same time
6a15bb7 [Sandy Ryza] Small fix
a2278c0 [Sandy Ryza] Respond to review comments
6ef592e [Sandy Ryza] SPARK-1813. Add a utility to SparkConf that makes using Kryo really easy
Update JavaCustomReceiver.java

Changed the usage string to correctly reflect the file name.

Author: Karthik <karthik.gomadam@gmail.com>

Closes #2699 from namelessnerd/patch-1 and squashes the following commits:

8570e33 [Karthik] Update JavaCustomReceiver.java
use isRunningLocally rather than runningLocally

runningLocally is deprecated now

Author: CrazyJvm <crazyjvm@gmail.com>

Closes #2879 from CrazyJvm/runningLocally and squashes the following commits:

bec0b3e [CrazyJvm] use isRunningLocally rather than runningLocally