Restore calling DrawUnhandledMissingTextures, but only for final eye render.
(after verifying that glitches remain repaired)
Elevate eye shift to renderer camera position, not just OpenGL camera, to reduce culling artifacts.
Implement late-scheduled head tracking in Rift mode
Add comment about remaining yaw discontinuity
Reset pitch and roll when leaving Rift mode.
Increment version number to 1.8.6_e
Create installer for GZ3Doom 1.8.6_e