Merge pull request #99 from ankurdave/only-dynamic-pregel

Remove static Pregel; take maxIterations in dynamic Pregel
Merge pull request #91 from amplab/standalone-pagerank

Standalone PageRank
Load edges in columnar format

In GraphLoader.edgeListFile, load edges directly into EdgePartitions,
avoiding repartitioning.
Don't partition edges by default; refactor

Instead, expose Graph.partitionBy(PartitionStrategy).
Fix argument bug and closure capture
Clean up imports in EdgeRDD