Revert "Merge pull request #310 from jyunfan/master"

This reverts commit 79b20e4dbe3dcd8559ec8316784d3334bb55868b, reversing
changes made to 7375047d516c5aa69221611f5f7b0f1d367039af.
Response to Reynold's comments
Add SparkConf support in Python
Changes to allow fate sharing of drivers/executors and workers.
Documentation and adding supervise option
Adding driver ID to submission response
Fix some other Python tests due to initializing JVM in a different way

The test in context.py created two different instances of the
SparkContext class by copying "globals", so that some tests can have a
global "sc" object and others can try initializing their own contexts.
This led to two JVM gateways being created since SparkConf also looked
at pyspark.context.SparkContext to get the JVM.
TODO clean-up
Add Python docs about SparkConf
Slight change to retry logic
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
Respect supervise option at Master
Fix a few settings that were being read as system properties after merge
Fix a change that was lost during merge
Added tests for SparkConf and fixed a bug

Typesafe Config caches system properties the first time it's invoked
by default, ignoring later changes unless you do something special
Address Aaron's comments
Fix some Python docs and make sure to unset SPARK_TESTING in Python
tests so we don't get the test spark.conf on the classpath.
Properly show Spark properties on web UI, and change app name property
Use Comparator instead of Ordering

lower object creation costs
Updated code style according to Patrick's comments