Cleanup in EvaluatorWorker status method.
Cleanup in EvaluatorWorker status method.

- Check on consumer thread periodically, raising an Exception to trigger restart if it dies unexpectedly. Moving the consumer in to a thread was preventing the process from being restarted when the consumer thread died (due to RabbitMQ outage, etc.).
abduld/bux-grader-framework,bu-ist/bux-grader-framework