(CDAP-509) Added ServiceWorkerContext.getSpecification() to expose the worker spec at runtime.
Merge pull request #569 from caskdata/feature/expose-spec

(CDAP-509) Added ServiceWorkerContext.getSpecification() to expose the worker spec at runtime.
Spark Integration: Streams support for Spark Jobs

Spark Integration: reactored
Spark Integration: Added readFromStream without time
Spark Integration: Fixed according to PR1
Spark Integration: Addressed comments of PR2
Spark with Streams unit tests
Spark Integration: Addressed PR3 comments
Spark Integration: Fixed function header
Spark Integration: Spark with streams unit test