1.2.12: Merge pull request #166 from HSF/dev

(1) add throttler
(2) improve conductor to check whether a message is already processed before replay the message, add delay parameter to delay the message replaying
(3) fix the issue to process that no panda jobs when a task is aborted.
(4) setup utc logging
(5) fix the function to suspend/resume receiver
(6) fix replaying messages for failed jobs.
(7) disable heartbeat for subscribing in stomp callings.
(8) disable syslog-ng