Spark now uses configure style

- Spark uses configurer style API : CDAP-382

Build running here: https://builds.cask.co/browse/CDAP-DUT316-2

This opens two more related (but independent to this merge) issues: 
CDAP-989: Doc changes for the Spark configurer style API
CDAP-990: Apps and Guide changes to use Spark configurer style API
This class is in cdap-api, as I said before, the goal is not to have guava dependency. In line 44, replace it with Collections.emptyMap.