Spark Integration: Streams support for Spark Jobs

Adds support to read Streams in Spark to resolve : CDAP-403

Build Running: https://builds.cask.co/browse/CDAP-DUT102-4

@anew : Please review. Thanks.
@jwang47: In case of false it throws exception so cant just use return. Might be able to do something though. Will look again.

@chtyim: Yes, I was skeptical about it. Will change it thanks.