Merge remote-tracking branch 'apache/master' into driver-test

bin/pyspark

conf/log4j.properties.template

...main/resources/org/apache/spark/log4j-defaults.properties

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

...a/org/apache/spark/deploy/master/ui/ApplicationPage.scala

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

.../scala/org/apache/spark/storage/ShuffleBlockManager.scala

docs/configuration.md

docs/python-programming-guide.md

docs/running-on-yarn.md

.../apache/spark/streaming/examples/JavaFlumeEventCount.java

...g/apache/spark/streaming/examples/JavaKafkaWordCount.java

...apache/spark/streaming/examples/JavaNetworkWordCount.java

.../org/apache/spark/streaming/examples/JavaQueueStream.java

.../org/apache/spark/streaming/examples/ActorWordCount.scala

...org/apache/spark/streaming/examples/FlumeEventCount.scala

...a/org/apache/spark/streaming/examples/HdfsWordCount.scala

.../org/apache/spark/streaming/examples/KafkaWordCount.scala

...a/org/apache/spark/streaming/examples/MQTTWordCount.scala

...rg/apache/spark/streaming/examples/NetworkWordCount.scala