Remove erroneous FAILED state for killed tasks.

Currently, when tasks are killed, the Executor first sends a
status update for the task with a "KILLED" state, and then
sends a second status update with a "FAILED" state saying that
the task failed due to an exception. The second FAILED state is
misleading/unncessary, and occurs due to a NonLocalReturnControl
Exception that gets thrown due to the way we kill tasks. This
commit eliminates that problem.
Fix yarn build after sparkConf changes
fix yarn-client
Merge pull request #320 from kayousterhout/erroneous_failed_msg

Remove erroneous FAILED state for killed tasks.

Currently, when tasks are killed, the Executor first sends a
status update for the task with a "KILLED" state, and then
sends a second status update with a "FAILED" state saying that
the task failed due to an exception. The second FAILED state is
misleading/unncessary, and occurs due to a NonLocalReturnControl
Exception that gets thrown due to the way we kill tasks. This
commit eliminates that problem.

I'm not at all sure that this is the best way to fix this problem,
so alternate suggestions welcome. @rxin guessing you're the right
person to look at this.
Merge pull request #323 from tgravescs/sparkconf_yarn_fix

fix spark on yarn after the sparkConf changes

This fixes it so that spark on yarn now compiles and works after the sparkConf changes.

There are also other issues I discovered along the way that are broken:
- mvn builds for yarn don't assemble correctly
- unset SPARK_EXAMPLES_JAR isn't handled properly anymore
- I'm pretty sure spark.conf doesn't actually work as its not distributed with yarn

those things can be fixed in separate pr unless others disagree.
Reorganize yarn related codes into sub projects to remove duplicate files.
Fix pom for yarn code reorgnaize commit
Change profile name new-yarn to hadoop2.2-yarn
Fix yarn/assemble pom file
Fix pom file for scala binary version
some code clean up for Yarn 2.2
Add README for yarn modules
Fix yarn/README.md and update docs/running-on-yarn.md
Update maven build documentation
A few clean up for yarn 2.0 code
Need to send dummy hello message to actually estabilish akka connection.
merge yarn/scheduler yarn/common code into one directory
Use unmanaged source dir to include common yarn code
Fix pom for build yarn/2.x with yarn/common into one jar
Clean up unused files for yarn