First cut at improved undo
Merge branch 'master' of https://github.com/highfidelity/hifi into improved_undo
More undo work
cleanup: remove unused Avatar::_mode

The mode, if it is required, should probably eventually live in
AvatarDAta since it will be determined by whatever engine is running the
avatar (script or interface) and then broadcast to the rest of the
world.  When we need it we'll add it back in the right place.
move _thrust from Avatar to MyAvatar
remove unused getElapsedTime*() methods
remove unused MoveTarget stuff from MyAvatar
removing unused motion-state timers
Merge branch 'master' of https://github.com/highfidelity/hifi into improved_undo
temp disable of screen flash for avatar collisions
Merge branch 'master' of https://github.com/highfidelity/hifi into improved_undo
Undo now fully support local subtrees
Merge branch 'master' of https://github.com/highfidelity/hifi into improved_undo
namechange CollisionFlags --> CollisionGroups
Pre CR tweaks
expose MyAvatar.collisionGroups to JS
expose COLLISION_GOUP_* constants to JS
add MyAvatar::_motionBehaviors (for obeyGravity)

Also reconcile Menu checkable set vs script-set collision groups.
Fix error introduced with gettimeofday removing + spelling mistake
Merge pull request #2727 from Atlante45/fix_error_from_remove_gettimeofday

Fix error introduced with gettimeofday removing + spelling mistake