Minor comment change.
Cruft removal.  We don't use Head::YawRate stuff.
Fixing mouselook.

Faceshift head rotations are stored separately and then integrated into
the final (rendered) head rotation at the right times but do not affect
the camera.
Merge pull request #1938 from AndrewMeadows/fix-mouselook

Fix mouselook
Merge branch 'master' of https://github.com/worklist/hifi into ray_cast_scripting