Fix racy shutdown that was copied from Sidekiq's racy shutdown.  Port of Sidekiq PR #2056 that includes Celluloid upgrade.
remove aws validation
use condvar rather than signalling in Manager#stop
Merge branch 'petergoldstein-feature/fix_racy_shutdown'
switch to v2 aws ruby sdk and do easy updates of aws object usage
no need for this reraise here
added queue and received message classes
remove hardcoded cmb endpoint
remove unneeded commented out code
received_messages need an id attr
s/parsers/parses/g
teach Processor to extend message invisibility for slow workers
support publishing to SNS topics
don't pass account_id key to aws config
only log "Process died" messages if it was non-successful exit