Merge pull request #2978 from Barnold1953/OculusOverlay

Fixed bug that disabled cursor for windows
fix for partial hand restore after hydra inactive
Allow floating point start/end frames and negative play speeds.
Merge pull request #2979 from AndrewMeadows/bug-fix

fix for partial hand restore after hydra goes inactive
Merge branch 'master' of https://github.com/highfidelity/hifi
Merge pull request #2980 from ey6es/master

Allow floating point start/end frames and negative play speeds.
Switched Oculus UI to hemisphere. Added curved semicircle UI
Merge branch 'master' of https://github.com/highfidelity/hifi into OculusOverlay