Make GraphImpl serializable to work around capture
Revert changes to examples/.../PageRankUtils.scala

Reverts to 04d83fc37f9eef89c20331c85291a0a169f75e6d:examples/src/main/scala/org/apache/spark/examples/bagel/PageRankUtils.scala.
Unwrap Graph.mapEdges signature
Vid -> VertexID
Pid -> PartitionID
Svdpp -> SVDPlusPlus
graph -> graphx
Add implicit algorithm methods for Graph; remove standalone PageRank
graph -> graphx in bin/compute-classpath.sh
Unpersist previous iterations in Pregel
Add Graph.unpersistVertices()
Unpersist previous iterations in GraphLab
Avoid recomputation by caching all multiply-used RDDs
graph -> graphx in log4j.properties
Undo 8b6b8ac87f6ffb92b3395344bf2696d5c7fb3798

Getting unpersist right in GraphLab is tricky.
Merge pull request #1 from jegonzal/graphx

ProgrammingGuide
Update graphx/pom.xml to mirror mllib/pom.xml
Remove commented code from Analytics
Remove EdgeTriplet.{src,dst}Stale, which were unused
Add back Bagel links to docs, but mark them superseded