Merge remote-tracking branch 'apache/master' into filestream-fix
Removed StreamingContext.registerInputStream and registerOutputStream - they were useless as InputDStream has been made to register itself. Also made DStream.register() private[streaming] - not useful to expose the confusing function. Updated a lot of documentation.
Enable compression by default for spills
Merge pull request #415 from pwendell/shuffle-compress

Enable compression by default for spills
Merge remote-tracking branch 'apache/master' into filestream-fix

Conflicts:
	streaming/src/main/scala/org/apache/spark/streaming/dstream/DStream.scala
Fixed loose ends in docs.
Merge pull request #416 from tdas/filestream-fix

Removed unnecessary DStream operations and updated docs

Removed StreamingContext.registerInputStream and registerOutputStream - they were useless. InputDStream has been made to register itself, and just registering a DStream as output stream cause RDD objects to be created but the RDDs will not be computed at all.. Also made DStream.register() private[streaming] for the same reasons.

Updated docs, specially added package documentation for streaming package.

Also, changed NetworkWordCount's input storage level to use MEMORY_ONLY, replication on the local machine causes warning messages (as replication fails) which is scary for a new user trying out his/her first example.