Fix demo playback when using the Rift
Fix color blending mangling the HUD
Don't roll the camera at player death when using an Oculus Rift
Prevent HUD from rolling when oculus sensors are reset
Allow setting IPD manually + fixes

-r_oculusrift_ipd now can be used set an ipd between 0 and 100mm
-If r_oculusrift_ipd is set outside of that range (e.g., -1) it will
revert to the value provided by LibOVR
-r_oculusrift_prediction now reports the value set
-Magnetic drift correction now reenables after a orientation reset
-Magnetic drift correction now creates and deletes necessary resources
when enabled/disabled
-Eliminated extra math in R_InitHMDRenderer()

Conflicts:
	Quake/gl_rmain.c
	Quake/gl_rmisc.c
	Quake/oculus_sdk.cpp
	Quake/oculus_sdk.h
	Quake/r_renderhmd.c
	Quake/r_renderhmd.h