FIX: fix issues with calling pause multiple times
FIX: fix issues with calling pause multiple times

All of the events that were in the msg_cache are now in the
generator on the stack.  As they are (re)processed they will be
added back to the msg_cache.  If pause is called again before the
next checkpoint they will be re-added to the generator stack.

dchabot/bluesky,ericdill/bluesky,klauer/bluesky,klauer/bluesky,ericdill/bluesky,dchabot/bluesky,sameera2004/bluesky,sameera2004/bluesky