Notify standalone deploy client of application death.

Usually, this isn't necessary since the application will be removed
as a result of the deploy client disconnecting, but occassionally, the
standalone deploy master removes an application otherwise.

Also mark applications as FAILED instead of FINISHED when they are
killed as a result of their executors failing too many times.
Merge pull request #515 from woggling/deploy-app-death

Notify standalone deploy client of application death.