merging upstream changes
fixing a typo in the VertexSetRDD docs
Merge pull request #33 from kellrott/master

Fixing graph/pom.xml
Strating to improve README.
Updating images so they render correctly.
Adding code example
Fixed issue with canonical edge partitioner.
Merge pull request #38 from jegonzal/Documentation

Improving Documentation
Merge remote-tracking branch 'spark-upstream/master'

Conflicts:
	project/SparkBuild.scala
removing unused commented code
added lineage tracking code
Removing potential additional shuffle dependency where an already partitioned RDD[(Vid, VD)] is repartitioned.
removing completely unnecessary map operation.
Adding additional type constraints to VertexSetRDD to help diagnose issues with recent benchmarks.
Merge branch 'cleanup'
Merge branch 'hash1' of https://github.com/rxin/incubator-spark into rxinBitSet
Added bitset to kryo register
Adding logical AND/OR, setUntil, and iterators to the BitSet.
Switching to the @rxin BitSet implementation for VertexSet Value tables.
Merge pull request #43 from amplab/FixBitSetCastException

Fix BitSet cast exception