Enhance job ui in spark ui system with adding pool information

Clean up web UI page headers

Add JSON path to master index page

Conflicts:
	core/src/main/scala/spark/deploy/master/ui/IndexPage.scala

Add data generator for K-means

Conflicts:
	docs/configuration.md

SPARK-842. Maven assembly is including examples libs and dependencies

Bug fix: SPARK-837

Build changes for ML lib

Also made it possible to specify the number of runs in KMeans.main().

Added property 'spark.executor.uri' for launching on Mesos.

Use the Char version of split() instead of the String one in MLUtils

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

Conflicts:
	core/src/main/scala/spark/SparkContext.scala
	core/src/main/scala/spark/scheduler/DAGScheduler.scala
	core/src/main/scala/spark/scheduler/SparkListener.scala
	core/src/main/scala/spark/scheduler/cluster/ClusterTaskSetManager.scala
	core/src/main/scala/spark/scheduler/cluster/TaskSetManager.scala
	core/src/main/scala/spark/scheduler/local/LocalTaskSetManager.scala
	core/src/main/scala/spark/ui/jobs/IndexPage.scala
	core/src/main/scala/spark/ui/jobs/JobProgressUI.scala

Add Apache license header to metrics system

Also don't build an assembly jar for them