Refactored out SendCache to SendVertexIdDataCache and SendCache.
Everything compiles.
All tests should run.
Next step is to add a test for the vertex combiner.
Should have fixed.
Fixed one bug for byte array partition.
Fixed another bug for too small of a message buffer.
Rebased.
Rebased.
Passes tests.  Need to add two more tests.
1)  Test VertexInputFormat and edge input format.
Done
2) Add a test to check that the vertex value combiner works.
Done
3)  Run an experiment to see if it is faster with my changes.
Passed 'mvn clean verify'
4) Now the edges are added for combined vertices.
5) Clean up.
GIRAPH-775: Vertex value combiner (aching)