Howard Trickey
ca5fd21bb5
Sometimes split would fail to make a face - make sure it doesn't crash if that happens. Chain finding code for holes would sometimes go back to same vertex on the face, which causes problems, so fixe that. Also, disallowed a cut that starts at a vertex or edge and cycles back to that same point in a face - this would make a face with a repeated vertex, which may not be handled by the rest of the system properly.