Merge remote-tracking branch 'upstream/trunk' into trunk
GIRAPH-840: Upgrade to netty 4 (pavanka via majakabiljo)
GIRAPH-853: Fix concurrency issue in GiraphMetrics (majakabiljo)
GIRAPH-854: fix for test fail due to GIRAPH-840 (pavanka via majakabiljo)
GIRAPH-848: Allowing plain computation with types being configurable (ikabiljo via majakabiljo)
Merge remote-tracking branch 'upstream/trunk' into trunk
Merge branch 'trunk' into GIRAPH-OOC
Merge branch 'trunk' of github.com:armax00/giraph into trunk
Merge branch 'trunk' into GIRAPH-OOC
revrite the I/O functions to avoid loosing exceptions