Reverting to Array based (materialized) output of all VertexSetRDD operations.
merging upstream changes
Merge pull request #51 from jegonzal/VertexSetRDD

Reverting to Array based (materialized) output in VertexSetRDD
Added GraphX to classpath.
Merge pull request #53 from amplab/rxin

Added GraphX to classpath.
Add source-attr versions of mrTriplets and aggN
Call source-attr version of aggN from Pregel