[scala] Simplify Operation Classes: No more Impl Classes
Fix guava dependency in flink-streaming-core to allow IDE local testing.
[FLINK-514] Fixed javadoc problems
[FLINK-514] Fix additional javadoc problems and add suppressions for certain compiler warnings.
[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
[FLINK-1124] Remove redundant HTML close tag
Repair guava dependencies
Guava shading fixes for eclipse and IntelliJ
[FLINK-1133] TypeExtractor resolves also variables inside Tuple-input
[FLINK-1133] TypeExtractor now also supports nested Tuple-input derivation

This closes #137
Move DeltaIteration Sanity Check to Base Operators

Is now in JoinOperator and CoGroupOperator. We don't need
the special Scala API sanity check anymore now since they
use java operators that now correctly check in the base
class.