Upgrade JobFactory to only return 1 job, not many for a descriptor since we're not using it in this way.

Updated the scheduler semaphore logic and reporting to be clearer.

Added a test to ensure scheduler pool times are correct.
Implements USERGRID-205

Added dead event to the job interface
Merge branch 'add-metrics' of https://git-wip-us.apache.org/repos/asf/incubator-usergrid into add-metrics