Compression codec change

Refactored Vector.apply(length, initializer) replacing excessive code with library method

(also removed unused variable ```ans``` as minor change)

Cleaned Partitioner & PythonPartitioner source by taking out non-related logic to Utils

Add Apache license header to metrics system

Renamed compressionOutputStream and compressionInputStream to compressedOutputStream and compressedInputStream.

Conflicts:
	project/SparkBuild.scala

Use Bootstrap progress bars in web UI

Minor mllib cleanup

Renamed Classification.scala to ClassificationModel.scala and Regression.scala to RegressionModel.scala

made SimpleUpdater consistent with other updaters

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.

Internal cleanup

Remove duplicate loss history in Gradient Descent

Also renamed MasterState to MasterStateResponse and WorkerState to WorkerStateResponse for clarity.

Conflicts:
	core/src/main/scala/spark/ui/jobs/IndexPage.scala

Totals for shuffle data and CPU time