Simplifiy API for camera mode transitions

Specify the "period" for the transition rather than the "rate".
Remove cruft: old avatar-avatar collision option
Split render options for head/body collision proxy

This makes the poor proxy shapes easier to see.
Merge branch 'master' of ssh://github.com/highfidelity/hifi into camera-occlusion

Conflicts:
	interface/src/Menu.h
	interface/src/avatar/Avatar.cpp
Merge branch 'master' of ssh://github.com/highfidelity/hifi into camera-occlusion
Moving "play slaps" code into its own method.

Cleaning up hand collision code in prep for more correct collisions.
Removing unused cruft: setHeadData() and friend
Remove Avatar::_hand, use AvatarData::_handData
Remove Avatar::_head, use AvatarData::_headData
Adding comment about bug as a reminder to fix.
Removing unused declaration of static method
Merge branch 'master' of ssh://github.com/highfidelity/hifi into cleanup

Conflicts:
	interface/src/avatar/MyAvatar.cpp
Putting new private method next to others.
Merge pull request #2024 from AndrewMeadows/cleanup

Cleanup hand and head