Fix issues reported by Reynold
Merge branch 'master' of github.com:mridulm/spark
If key is not valid, close connection
Be more aggressive and defensive in select also
Change indentation
Merge branch 'master' of github.com:mridulm/spark
Be more aggressive and defensive in all uses of SelectionKey in select loop
Spurious commit, reverting gitignore change
Add addition catch block for exception too
Merge branch 'master' of github.com:mridulm/spark
Merge pull request #586 from mridulm/master

Pull request to address issues Reynold Xin reported
Merge branch 'master' of github.com:mesos/spark
Merged Ram's commit on removing RDDs.

Conflicts:
	core/src/main/scala/spark/SparkContext.scala
Cleaned up Ram's code. Moved SparkContext.remove to RDD.unpersist.

Also updated unit tests to make sure they are properly testing for
concurrency.
Added SparkContext.cleanup back. Not sure why it was removed before ...
Changed the type of the persistentRdds hashmap back to
TimeStampedHashMap.
Remove spark-repl's extraneous dependency on spark-streaming
filter out Spark streaming block RDD and sort RDDInfo with id
Added removeRdd function in BlockManager.
Added the unpersist api to JavaRDD.