Added the singleton accessors
Adds in some thread controls
WIP
Add a deferred work set to handle the blocking on work
Use #pop semantics rather than sleeping
Add an instances accessor
Got a singleton deferred work manager
Remove noise from the test run
The QueueManager should no longer purge the deferred manager
Update the QueueManager specs to test for calls to the singleton
Fix up a couple of typos
Remove the old reference implementation
Add a sanity check to ensure  we don't block on #pop from two threads
Spec out some failure modes for hte deferred thread
Adds some pending specs to remind me...
Reduce the number of workers to reduce the chance that jobs get handled out of order
Report exceptions during tests
WIP
Stub out the broken tests for the time being
Clean up the crazy thread behaviour by not using Thread#kill.