first non-tested push on Gremlin Sacks feature -- Refs #330
All test cases pass. Still have not written 'sack specific' test cases, but the foundation is solid. All the GraphTraversal methods added. There are a few issues I have with the merging methods in Traverser  --- sorta awkward right now. Get that clean and test and then merge to master. Refs #330.
Added SackTest. Found a bug in GraphComputer where the local sideEffects in the distribution computation dont get the sack initialvalue/mergeoperator. This required me to clean up an old hack from long long ago that in turn, rectified this sack situation. Also, this hack greatly reduce object creation in TraversalVertexProgam and respective MapReduce computations. Cool. Refs #330.
cleanup to TreeMap.
Updated CHANGELOG and Fixed #330