Merge remote-tracking branch 'origin/master' into conf2

Conflicts:
	core/src/main/scala/org/apache/spark/SparkContext.scala
	core/src/main/scala/org/apache/spark/scheduler/DAGScheduler.scala
	core/src/main/scala/org/apache/spark/scheduler/TaskSchedulerImpl.scala
	core/src/main/scala/org/apache/spark/scheduler/cluster/ClusterTaskSetManager.scala
	core/src/main/scala/org/apache/spark/scheduler/local/LocalScheduler.scala
	core/src/main/scala/org/apache/spark/util/MetadataCleaner.scala
	core/src/test/scala/org/apache/spark/scheduler/TaskResultGetterSuite.scala
	core/src/test/scala/org/apache/spark/scheduler/TaskSetManagerSuite.scala
	new-yarn/src/main/scala/org/apache/spark/deploy/yarn/Client.scala
	streaming/src/main/scala/org/apache/spark/streaming/Checkpoint.scala
	streaming/src/main/scala/org/apache/spark/streaming/api/java/JavaStreamingContext.scala
	streaming/src/main/scala/org/apache/spark/streaming/scheduler/JobGenerator.scala
	streaming/src/test/scala/org/apache/spark/streaming/BasicOperationsSuite.scala
	streaming/src/test/scala/org/apache/spark/streaming/CheckpointSuite.scala
	streaming/src/test/scala/org/apache/spark/streaming/InputStreamsSuite.scala
	streaming/src/test/scala/org/apache/spark/streaming/TestSuiteBase.scala
	streaming/src/test/scala/org/apache/spark/streaming/WindowOperationsSuite.scala