GIRAPH-665: Reduce ZooKeeper output in tests by changing log level from INFO to ERROR (aching)
GIRAPH-666: Netty execs threads and metrics threads don't get
cleaned up properly (aching)
GIRAPH-608: Spelling error in Combiner.java (Michael Aro via aching)
GIRAPH-667: Decouple Vertex data and Computation, make Computation and Combiner classes switchable  (majakabiljo)
GIRAPH-620: Website Documentation: How to use Hive I/O with Giraph
Merge remote-tracking branch 'origin/trunk' into docs

Conflicts:
	CHANGELOG