Groundwork for transfering reliable fetch working queue back to public queue on graceful shutdown.
Don't bother with hard shutdown if we signaled a shutdown.
Use bulk_requeue instead of terminate.
Split out requeue/shutdown as before.
Rename terminate to shutdown to avoid name conflicts with Celluloid; up the retry time for waiting for jobs to finish.
Move bulk_requeue back to class method.
Merge pull request #1358 from jonhyman/feature/transfer-on-shutdown

Groundwork for transfering reliable fetch working queue back to public q...