AU GUIs basically working, though unfinished; push up dialog for massive split operat...

AU GUIs basically working, though unfinished; push up dialog for massive split operations (still in progress); fix problem where peakfile is slightly older than audio data even though it is ready to use (debugging output still present); move sync-menu code to libs/gtkmm2ext for linkage reasons; prevent flush_pending() calls from "top menu" items on OS X from locking the GUI; try to make adding lots of regions (e.g. from split-at-points) scale a bit better; SAE version has no timecode mode for audio clocks

git-svn-id: svn://localhost/ardour2/branches/2.0-ongoing@3038 d708f5d6-7413-0410-9779-e7cbd77b26cf