GIRAPH-923: Upgrade Netty version to a latest stable one (pavanka)
GIRAPH-713: Provide an option to do request compression (pavanka)
GIRAPH-925: Unit tests should pass even if zookeeper port not available (edunov via pavanka)
GIRAPH-903: Detect crashes of Netty threads (edunov via pavanka)
GIRAPH-912: Support succinct representation of messages in messagestores (pavanka)
GIRAPH-929: setIfUnset for EnumConfOption (pavanka)
GIRAPH-921: Create ByteValueVertex to store vertex values as bytes without object instance (akyrola via majakabiljo)
GIRAPH-924: Fix checkpointing (edunov via majakabiljo)