graph -> graphx in pom.xml
Remove unused HashUtils class
Clean up GraphGenerators
Improve docs for VertexRDD
Move VertexIdToIndexMap into impl
Minor cleanup to docs
Add doc for Algorithms
Revert changes to Spark's (PrimitiveKey)OpenHashMap; copy PKOHM to graphx
Revert GraphX changes to SparkILoopInit

The changes were to support a custom banner in spark-shell for use by
graphx-shell, but once GraphX is merged into Spark, a separate shell
will be unnecessary.
Fix scaladoc warnings
Remove blank lines added to Spark core
Finish d1d2b6d9b6b5f9cc45047507368a816903722d9e
Add GC note to GraphLab
Soften wording about GraphX superseding Bagel
More edits.