Merge branch 'master' of https://github.com/worklist/hifi into i-can-always-move
Merge branch 'master' of https://github.com/worklist/hifi into i-can-always-move
Leap interface and Avatar: left-hand IK works for Leap interface.

This is in and smooth, and there's a decision to be made:
In the case where only one hand is visible, we have to decide if it's the left or right hand. Currently it's simple, based on which side it's detected on.
So far this seems to work best, in the (very) common case where hands go in/out of the sensor's field frequently.
We could also use a history-based heuristic to hold one hand as left/right, but that means that when it guesses wrong the error lingers.
Detecting handedness based on where the thumbs are would be better, but is unreliable on the Leap.
I went for the simple/clear version, but we can do whatever we want.
Cleanup and simplification per feedback
Merge pull request #1057 from machinelevel/dev4

Leap interface and Avatar: left-hand IK works for Leap interface.
make mouse cursor hiding more aware of focused window and bounds
Merge pull request #1058 from ZappoMan/hide_cursor

make mouse cursor hiding more aware of focused window and bounds
first cut at added voxel node memory usage debugging to client and server
added more stats to voxel server status
move loading of voxel file to the persist thread so that assignment client will load voxel server faster
added additional debugging of VoxelNode memory usage, shrunk size of VoxelNode by better alignment
Merge pull request #1059 from ZappoMan/voxel_memory_stats

Voxel memory stats/Load voxels on persist thread/Save memory with VoxelNode size savings
Merge branch 'master' of https://github.com/worklist/hifi into i-can-always-move
All onscreen text, overlay OFF when stats are off
Merge pull request #1061 from PhilipRosedale/option_to_hide_all_overlay

Option to hide all overlay