Completed worklist job #19486

Job #19486  Don't render the duplicate triangles between adjacent
voxels.

Added checkable item to "developer" menu to activate/deactivate cull
shared faces.

Cull all shared voxel faces regardless of distribution in the octree.
Includes leaf to leaf, leaf to non-leaf, and non-leaf to non-leaf
comparison of contiguous faces.

Added new GL primitive renderer to manage the transfer of cube faces
from the voxel system to GL.

Added some useful classes for queue and lock management.

Modified statistics collection to report number of completely culled
nodes. Extra debugging info also includes the interior occlusions bit
mask of leaf voxels.