Merge branch 'clean1' of github.com:amplab/graphx into clean1
Added an optimized count to VertexSetRDD.
Made all VertexPartition internal data structures private.
Merge branch 'subgraph-test' of github.com:ankurdave/graphx into clean1

Conflicts:
	graph/src/main/scala/org/apache/spark/graph/impl/VertexPartition.scala
Merged Ankur's pull request #80 and fixed subgraph.
Scheduler quits when createStage fails.

The current scheduler thread does not handle exceptions from createStage stage while launching new jobs. The thread fails on any exception that gets triggered at that level, leaving the cluster hanging with no schduler.
Created EdgeRDD.
Removed PartitionStrategy from GraphImpl.
Memoize preferred locations in ZippedPartitionsBaseRDD so preferred location computation doesn't lead to exponential explosion.
Memoize preferred locations in ZippedPartitionsBaseRDD so preferred location computation doesn't lead to exponential explosion.

(cherry picked from commit e36fe55a031d2c01c9d7c5d85965951c681a0c74)
Signed-off-by: Reynold Xin <rxin@apache.org>
Merge pull request #216 from liancheng/fix-spark-966

Bugfix: SPARK-965 & SPARK-966

SPARK-965: https://spark-project.atlassian.net/browse/SPARK-965
SPARK-966: https://spark-project.atlassian.net/browse/SPARK-966

* Add back `DAGScheduler.start()`, `eventProcessActor` is created and started here.

  Notice that function is only called by `SparkContext`.

* Cancel the scheduled stage resubmission task when stopping `eventProcessActor`

* Add a new `DAGSchedulerEvent` `ResubmitFailedStages`

  This event message is sent by the scheduled stage resubmission task to `eventProcessActor`.  In this way, `DAGScheduler.resubmitFailedStages()` is guaranteed to be executed from the same thread that runs `DAGScheduler.processEvent()`.

  Please refer to discussion in [SPARK-966](https://spark-project.atlassian.net/browse/SPARK-966) for details.
Log exception in scheduler in addition to passing it to the caller.
Code Styling changes.
Merge pull request #219 from sundeepn/schedulerexception

Scheduler quits when newStage fails

The current scheduler thread does not handle exceptions from newStage stage while launching new jobs. The thread fails on any exception that gets triggered at that level, leaving the cluster hanging with no schduler.
Created an algorithms package and put all algorithms there.
Made akka capable of tolerating fatal exceptions and moving on.
Use specialized shuffler for aggregation.
Cleanup and documentation of SparkActorSystem
Fixed problem with scheduler delay
Mark partitioner, name, and generator field in RDD as @transient.
Cleanup and documentation of SparkActorSystem