Auto moving of Rift window to Rift on Mac

- Attempt to detect the Oculus Rift display and move the Oculus window to it (Mac)
- Remember the main window associated with the Rift display
- Add a new per-frame tick function in Objective C land to facilitate per-frame Mac specific stuff
Merge branch 'WemoVRPlayerDev' of https://github.com/wemomedia/xgit_vlc into WemoVRPlayerDev

Conflicts:
	modules/video_filter/wemovr.cpp