ImageEngine/gaffer — pull request #845 by johnhaddon (2014-05-16 17:39:32+00:00)
Title: IPR Pausing

This implements #646, and fixes a deadlock I discovered in the process. I think another deadlock exists (try undoing/redoing the removal of a connection), but I'll tackle that while taking care of some of the other IPR tickets later (the deadlocks aren't something introduced by this branch - they're preexisting).