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 : I discussed between UnsupportedOperationException and IllegalStateException with @anew and he suggested to have IllegalState. I will wait for him to confirm on this.