SPARK-829: scheduler shouldn't hang if a task contains unserializable objects in its closure.
Scheduler code style cleanup.
SPARK-829: scheduler shouldn't hang if a task contains unserializable objects in its closure.
Moved non-serializable closure catching exception from submitStage to submitMissingTasks
Added comments on task closure serialization.
Moved non-serializable closure catching exception from submitStage to submitMissingTasks
Merge pull request #726 from rxin/spark-826

SPARK-829: scheduler shouldn't hang if a task contains unserializable objects in its closure
Merge pull request #727 from rxin/scheduler

Scheduler code style cleanup.
Build metrics system framwork
Add Master and Worker instrumentation support
Update metric source support for instrumentation
MetricsSystem refactor
refactor metrics system
1.change source abstract class to support MetricRegistry
2.change master/work/jvm source class
Code clean and remarshal
Add dependency of Codahale's metrics library
Add Executor instrumentation
Add default properties to deal with no configure file situation
Add metrics system unit test
Remove twice add Source bug and code clean
Add metrics source of DAGScheduler and blockManager

Conflicts:

	core/src/main/scala/spark/SparkContext.scala
	core/src/main/scala/spark/SparkEnv.scala