add an example that runs wordcount over file datasets
renamed app to FileSetExample; addressed John's comments
addressing more of JJ's comments
Merge branch 'feature/file-example' into develop
Spark Integration: fix failing spark unit test
Merge pull request #681 from caskdata/feature/fix-spark-unit

Spark Integration: fix failing spark unit test
CDAP-538: Ported procedures to services of SparkKMeans app; Updated scripts.
CDAP-538: Replaced sendError to sendString for response.
CDAP-538: Added tests for SparkKMeans app; Send response as string instead of Json.