GIRAPH-842: option to dump histogram of memory usage when heap is low on memory (pavanka)
GIRAPH-918: GIRAPH-908 has a small bug reg counting entries (pavanka)
GIRAPH-915: With BigDataIO some messages can get ignored (majakabiljo via pavanka)
GIRAPH-922: SimpleEdgeStore has a bug causing NPE (pavanka)
fix build error (pavanka)
GIRAPH-919: Add worker to worker communication (majakabiljo)
GIRAPH-916: Wrong number of vertices stored reported to command line (majakabiljo)