Fix issue with unrecognized key presses
Implement OVR time warping support + cleanup

-Removed vr_ovr_distortion, vr_ovr_autoscale, and vr_ovr_filtermode
-Added vr_ovr_autoprediction - uses libovr provided motion prediction
times
-Added vr_ovr_maxfov - sets distortion to occupy the entire screen
-Added vr_ovr_timewarp - enables timewarping
-Removed some dead code
-Removed some dead menu items