Blender Git Loki

Fix crash opening some .blend files on OS X 10.8 with double click or drag and
drop onto the application.

It seems something changed in the operating which makes our method of releasing
windows crash. Previously we called [m_window release], but on 10.8 this does
not remove the window from [NSApp orderedWindows] and perhaps other places,
leading to crashes. So instead we set setReleasedWhenClosed back to YES right
before closing, which will then do the cleanup for us.