Version bump to 0.6.1
improve error handling:
 by default don't retry :worker_error
 allow :retry_limit for :worker_error
 cancel the job unless :errors_allowed
 monitor offline workers and poll/reinstate them
 check that a 'finished' status has been sent from worker or its not considered finished
 report unhandled exceptions in worker back to queue so it can be raised as a :worker_error
 add handle_worker_error callback to worker controller
added error reporting by email
improved startup without command
show email debug when start command is test_email
improve error message when no config path specified
fix cancel message getting lost
added support for process monitoring
fixed spec to support missing finished message error
more error reporting
added require for TCPSocket