Blender Git Loki

Various convex hull fixes

* Lower the required number of vertices from four to three. The new
backend correctly outputs a triangle in this case.

* Fix the check for the number of input vertices. Before it was
counting total number of input elements including edges and faces.

* Don't mark edges as holes if they are loose.

* Don't allow duplicate faces to be created.

* If use_existing_faces isn't enabled, but a face in the convex hull
has the same vertices as an existing face in the mesh, mark it as
output geometry rather than interior geometry.

* Fixes bug [#32960] Convex hull operator crashes when 'make holes' is
selected.
projects.blender.org/tracker/?func=detail&atid=498&aid=32960&group_id=9