When we add (or recolor) a voxel, make sure it has no children.  When we
attempt to remove a voxel that would be a child of a larger solid one, carve
up the parent.
More editing progress.  Now there are threading issues.  Joy!
lengthOfVoxelData already includes the length of the color data.
Let's do some locking to prevent simultaneous access from different threads.
Merge branch 'master' of https://github.com/worklist/hifi
Fixed the major bug, which is that non-leaves were being collapsed.  Update
full VBO on deletion, since otherwise we don't see the update.
Removed debug code, more tests for staged-for-deletion.
Better way of coming up with a contrasting color.
Start out with voxel editing disabled; let the add/delete/color buttons toggle
the mode.
Don't set the renderFullVBOs flag; that's not the problem.
Merge pull request #295 from ey6es/master

Voxel deletion, bugfixes for voxel code.