Blender Git Loki

Improve hole-detection

- use vert-stack instead of edges for walking edge-links (avoid a nested loop).
- count verts as well as edges when walking over edge-links.
- don't over-alloc vert arrays (was using total edges * 2)
- use the simpler linklist prepend since order if edges is no longer relied on.
- order edges/group walking for minimal sorting.
- use the dominant axis to order verts instead of abusing the vertex normal.