The code was for wxCocoa, which is a dead implementation of wxWidgets. wxOSX/Cocoa does not need this hack anymore. And the code is causing linking errors due to using private structures in wxCocoa.
Revert fffb138b81
Add a new Project class which is responsible for everything related to
opening and closing audio, video, subtitles, timecodes and keyframes.
This pulls almost everything not directly related to playing audio/video
out of the audio and video controllers, pulls more crap out of
FrameMain, and happens to make things a little simpler in the process.