Blender Git Loki

adaptive_cloth: Mesh: collapse edge: all v1 should point to n1

Sometimes, `n1` will have still have verts attached to it, so it makes
sense to make those verts point to `n2` but keep their UV coordinates
since attempting to merge verts not joined by edges can lead to lot of
issues. So essentially, extra `v1`s becomes `v2`s.