yet (R.vn and R.vlr no longer exist, and were needed to get the image mapped
right). Works esp. well with Subsurfs. Sensitive to vertex normal issues
in Simple and Mesh modes.
-Also porting Simple Subdivide. Subdivides mesh at rendertime w/o changing
shape, for smooth displace and Radiosity.
-Removed an unused var from KnifeSubdivide.