fixing models not rendering sometimes
Merge branch 'master' of https://github.com/worklist/hifi into modelserver
cleanup debug
Merge pull request #2858 from ZappoMan/modelserver

Fix bug where sometimes models don't render
When PrioVR is connected but head rotation is unavailable, use Faceshift
rotation.
Try smoothing the PrioVR input over a couple of frames.
Fixed compile error.
Merge pull request #2860 from ey6es/priority

PrioVR tweaks: average over two frames, use Faceshift head rotation when PrioVR one is unavailable.