Merge branch 'master' of https://github.com/apache/incubator-spark into indexedrdd_graphx

bin/slaves.sh

bin/spark-daemon.sh

bin/spark-daemons.sh

core/src/main/scala/org/apache/spark/SparkContext.scala

core/src/main/scala/org/apache/spark/SparkHadoopWriter.scala

core/src/main/scala/org/apache/spark/TaskContext.scala

...cala/org/apache/spark/broadcast/BitTorrentBroadcast.scala

.../main/scala/org/apache/spark/broadcast/MultiTracker.scala

...main/scala/org/apache/spark/broadcast/TreeBroadcast.scala

.../apache/spark/executor/CoarseGrainedExecutorBackend.scala

core/src/main/scala/org/apache/spark/executor/Executor.scala

...in/scala/org/apache/spark/network/ConnectionManager.scala

.../main/scala/org/apache/spark/scheduler/DAGScheduler.scala

...main/scala/org/apache/spark/scheduler/TaskScheduler.scala

...la/org/apache/spark/scheduler/TaskSchedulerListener.scala

...org/apache/spark/scheduler/cluster/ClusterScheduler.scala

...pache/spark/scheduler/cluster/ClusterTaskSetManager.scala

...spark/scheduler/cluster/CoarseGrainedClusterMessage.scala

...ark/scheduler/cluster/CoarseGrainedSchedulerBackend.scala

...spark/scheduler/cluster/SparkDeploySchedulerBackend.scala