Give the event loader some love
Give the event loader some love

* Remove messenger acks when loading events, to improve performance
* Add option to limit loading up to a certain timestamp
* Add option to specify number of messages to load per iteration
* Various cosmetic code changes

pombredanne/github-mirror,jeffmcaffer/github-mirror,jeffmcaffer/github-mirror,gousiosg/github-mirror,pombredanne/github-mirror,gousiosg/github-mirror,owenchen93/github-mirror