Adding EventStream method to spark adaptor
Adding Variable method to spark code adaptor
Adding Function methods to spark core adaptor
Update examples, slight refactor and more tests
Merge pull request #161 from hybridgroup/variables-and-functions

Variables and functions for spark adaptor
Merge branch 'dev' into event-stream

Conflicts:
	platforms/spark/spark_core_adaptor.go
Refactor and add tests
Merge pull request #162 from hybridgroup/event-stream

Adding EventStream method to spark adaptor
Merge branch 'dev'