Throw exception if task result exceeds Akka frame size.

This partially addresses SPARK-747.
Abort job if result exceeds Akka frame size; add test.
Fix running on yarn documentation
Filter out nulls - prevent NPE
Fix documentation to use yarn-standalone as master
Hope this does not turn into a bike shed change
Updated Scala version in docs generation ruby script.
Updated Scala version in docs generation ruby script.
Merge pull request #615 from rxin/build-fix

Maven build fix & two other small changes
Fix example jar name
Merge branch 'master' of github.com:mesos/spark
Merge branch 'master' of https://github.com/mridulm/spark
Fixed a couple typos and formating problems in the YARN documentation.
Changed the logging level from info to warning when addJar(null) is
called.
Merge pull request #610 from JoshRosen/spark-747

Throw exception if TaskResult exceeds Akka frame size
Fixed memory leak in DAGScheduler- needs more tests under error conditions.
Removed copyright
CSD version numbering and distribution management
Bump some dependencies, pin others, for Scala 2.9.2
DAGSchedulerSuite now part of core/src/test/scala/spark/scheduler