Merge branch 'master' of https://github.com/mesos/spark into bootstrap-update

Conflicts:
	core/src/main/scala/spark/ui/jobs/IndexPage.scala
Fixed continuity of executorToTasksActive, changed color of progress bars
Moved DeployMessage's into its own DeployMessages object.
Also renamed MasterState to MasterStateResponse and WorkerState to WorkerStateResponse for clarity.
Open up Job UI ports (33000-33010) on EC2 clusters
Removed Cache and SoftReferenceCache since they are no longer used.
Moved block manager messages into BlockManagerMessages object.
Moved all StandaloneClusterMessage's into StandaloneClusterMessages object.
Clarify how regVal is computed in Updater docs
initial externalization of ParallelCollectionRDD's split
Update the Python logistic regression example to read from a file and
batch input records for more efficient NumPy computations
Merge pull request #745 from shivaram/loss-update-fix

Remove duplicate loss history in Gradient Descent
Merge pull request #746 from rxin/cleanup

Internal cleanup
refactor job ui with pool information
refactor codes less than 100 character per line
Do not inherit master's PYTHONPATH on workers.

This fixes SPARK-832, an issue where PySpark
would not work when the master and workers used
different SPARK_HOME paths.

This change may potentially break code that relied
on the master's PYTHONPATH being used on workers.
To have custom PYTHONPATH additions used on the
workers, users should set a custom PYTHONPATH in
spark-env.sh rather than setting it in the shell.
Use File.pathSeparator instead of hardcoding ':'.
made SimpleUpdater consistent with other updaters
Added property 'spark.executor.uri' for launching on Mesos without
requiring Spark to be installed. Using 'make_distribution.sh' a user
can put a Spark distribution at a URI supported by Mesos (e.g.,
'hdfs://...') and then set that when launching their job. Also added
SPARK_EXECUTOR_URI for the REPL.
Merge pull request #748 from atalwalkar/master

made SimpleUpdater consistent with other updaters
+ bug fixes;

test added

Conflicts:

	core/src/test/scala/spark/KryoSerializerSuite.scala