[Deb] fix package of Spark classes adding org.apache prefix in scripts embeded in .deb
Added logging of scheduler delays to UI
Memoize preferred locations in ZippedPartitionsBaseRDD so preferred location computation doesn't lead to exponential explosion.

(cherry picked from commit e36fe55a031d2c01c9d7c5d85965951c681a0c74)
Signed-off-by: Reynold Xin <rxin@apache.org>
Fixed problem with scheduler delay
Added stageId <--> jobId mapping in DAGScheduler
  ...and make sure that DAGScheduler data structures are cleaned up on job completion.
  Initial effort and discussion at https://github.com/mesos/spark/pull/842
Actor instead of eventQueue for LocalJobCompleted
Fixed intended side-effects
Removed redundant residual re: reverted refactoring.
Improved comment
Refactoring to make job removal, stage removal, task cancellation clearer
Cleaned up job cancellation handling
Tightly couple stageIdToJobIds and jobIdToStageIds
Local jobs post SparkListenerJobEnd, and DAGScheduler data structure
cleanup always occurs before any posting of SparkListenerJobEnd.
Synchronous, inline cleanup after runLocally
SparkListenerJobStart posted from local jobs
Change the name of input ragument in ClusterScheduler#initialize from context to backend.

The SchedulerBackend used to be called ClusterSchedulerContext so just want to make small
change of the input param in the ClusterScheduler#initialize to reflect this.
Updated documentation about the YARN v2.2 build process
more docs
Minor doc fixes and updating README
Adding disclaimer for shuffle file consolidation