Accept-FullScreen warning not rendering with preserve-3d

[pehrlich]

In windows, we had fullscreen automatically jump to the correct desktop. This meant that it was impossible to accept the fullscreen without unplugging the oculus display.

[caseyyee]

For now, the workaround to this issue is to request full-screen with pointer-lock on the users primary display. Once you do that, you can request full-screen without the permission blocking UI interactions on the Rift.