Nudge function added. Testing nudge.
Nudge code working for nudge that is greater than or equal to leaf size.
Got rid of delete in nudge. Create is already destructive.
Add VoxelNudgeMode and preliminary UI grid for nudging.
Merge branch 'nudge'

Conflicts:
	interface/src/Menu.cpp
	libraries/voxels/src/VoxelTree.h
Switching nudge to cut/paste implementation. Preliminary.
Merge remote-tracking branch 'upstream/master'
Merge branch 'master' of https://github.com/worklist/hifi
UI for nudge completed!
Merge remote-tracking branch 'upstream/master'
Add nudgeVoxel shading in grid. Fix erase bug.
Merge branch 'master' of https://github.com/worklist/hifi
Remove magic numbers, fix spacing, and other code clean up in nudge code.
When devices become inactive (including when Faceshift reports loss of
tracking), smoothly restore neutral head rotation/lean.
Merge pull request #916 from LionTurtle/master

Nudge
Reduced the restore rate.
Merge branch 'master' of https://github.com/worklist/hifi
Align the eyelids to the top of the iris.
Tweak to blink angles.
Merge pull request #918 from ey6es/master

Restore head rotation/lean to neutral when not tracking, have eyelids follow top of iris.