Add flag for enclosing edge voxels?

[bnolan]

Currently the mesher doesn't generate meshes for the edge voxel. It is an easy change to make the code mesh the outside edges of the voxel chunks? Otherwise I can oversize the voxel data field before meshing (eg extend it to 34x34x34 with a 1 voxel empty border), but that's super inefficient.

See this block which is at z position 31 in a 32x32x32 field.

[bnolan]

Hmm, doing that would break the ambient occlusion, I guess this change is a bit harder. Maybe I need to look at making the mesher look at surrounding voxels while calculating?