add file dataset; hook up with map reduce
minor corrections
fixing some camel case dataSet occurrences
add helpers to set runtime arguments
address review
adding static helper methods to configure file properties
(CDAP-711) Added support for `@DefaultValue` in Service handler.
address terence's comments
Merge branch 'develop' into feature/file-ds
CDAP-32 Add timeout for audit log verification in ExternalAuthenticationServerTestBase
Merge pull request #663 from caskdata/feature/test-defaultvalue

(CDAP-711) Added support for `@DefaultValue` in Service handler.
Merge branch 'feature/file-ds' into develop
Merge pull request #666 from caskdata/feature/improve-external-auth-test

CDAP-32 Add timeout for audit log verification in ExternalAuthenticationServerTestBase
CYB #91: Unit test for Spark Page Rank example