BlockManager UI.
code Formatting
Nicer storage level format on RDD page
Merge branch 'master' into blockmanagerUI

Conflicts:
	core/src/main/twirl/spark/deploy/worker/index.scala.html
Merge branch 'master' into blockmanagerUI
Refactor BlockManager UI and adding worker details.
Merge branch 'master' into blockmanagerUI
Provide and expose a default Hadoop Configuration.

Any "hadoop.*" system properties will be passed along into configuration.
Check for AWS_ACCESS_KEY_ID/AWS_SECRET_ACCESS_KEY environment variables.

For custom properties, use "spark.hadoop.*" as a prefix instead of just "hadoop.*".
Fix invalid asInstanceOf cast.
Use hadoopConfiguration for default JobConf in PairRDDFunctions.
Pass a new Configuration that wraps the default hadoopConfiguration.
Add spark.executor.memory to differentiate executor memory from spark-shell memory.
Merge remote-tracking branch 'dennybritz/blockmanagerUI' into blockmanager_ui

Conflicts:
	core/src/main/scala/spark/RDD.scala
	core/src/main/scala/spark/storage/BlockManagerMaster.scala
	core/src/main/scala/spark/storage/StorageLevel.scala
Add __repr__ to Accumulator; fix bug in sc.accumulator
Merge pull request #361 from mesos/streaming

Merge Streaming into master
Add RDD checkpointing to Python API.
Add checkpointFile() and more tests to PySpark.
Update checkpointing API docs in Python/Java.
Clean up setup code in PySpark checkpointing tests