GIRAPH-612: Improve website for upcoming release (aching)
Fixing GIRAPH-612 to pass 'mvn clean verify' without findbugs problem.
GIRAPH-615: Add support for multithreaded output (majakabiljo)
GIRAPH-543: Fix PageRankBenchmark and make WeightedPageRankBenchmark (majakabiljo)
GIRAPH-613
GIRAPH-613
GIRAPH-613
GIRAPH-616: Decouple vertices and edges in DiskBackedPartitionStore and avoid writing back edges when the algorithm does not change topology.
GIRAPH-616
GIRAPH-614: SplitMasterWorker=false is broken (majakabiljo)
Merge remote-tracking branch 'origin/trunk' into vertex-runner

Conflicts:
	CHANGELOG
	giraph-core/src/main/java/org/apache/giraph/benchmark/PageRankBenchmark.java
	giraph-core/src/main/java/org/apache/giraph/conf/GiraphConfiguration.java
	giraph-core/src/test/java/org/apache/giraph/io/TestJsonBase64Format.java