checkstyle fixes
GIRAPH-581: More flexible Hive output (majakabiljo)
GIRAPH-587: Refactor configuration options (nitay)
GIRAPH-588: GIRAPH-588: More flexible Hive input (majakabiljo)
GIRAPH-597: Don't reuse vertex by default in SimpleHiveToVertex (majakabiljo)
GIRAPH-594: auto set reusing objects (nitay)
GIRAPH-593: Update Hive IO performance improvements (nitay)
Merge remote-tracking branch 'origin/trunk' into yourkit-profiling

Conflicts:
	giraph-core/src/main/java/org/apache/giraph/conf/GiraphConfiguration.java