[streaming] Added CoBatchReduceInvokable, CoWindowReduceInvokable, CoGroupedBatchReduceInvokable, CoGroupedWindowReduceInvokable
[streaming] Reduce and GroupReduce invokable refactor and performance tweak
[streaming] ConnectedDataStream API  and operator cleanup + modified windowReduceGroup functionality
[streaming] Improved tests for CoReduceInvokables
Guava shading issue fix for Eclipse