Bone Heat Weighting

===================

This is a new automatic vertex weighting method, next to the existing
envelope based method. The details are here:

http://www.blender.org/development/current-projects/changes-since-244/skinning/

This is based on section 4 of the paper:

"Automatic Rigging and Animation of 3D Characters"
Ilya Baran and Jovan Popovic, SIGGRAPH 2007

Implementation Notes:

- Generic code for making mesh laplacian matrices has been added, which
  is only used by bone heat weighting at the moment.
- Bone to vertex visibility checking is done with the raytracing code.
- Fixed an issue in the subsurf limit calculation function, where the
  position of vertices on boundary edges was wrong. It is still not the
  correct position, but at least it's in the neighbourhood now.

source/blender/include/BIF_poseobject.h

@@ -58,7 +58,7 @@ void free_posebuf(void);
 void copy_posebuf (void);
 void paste_posebuf (int flip);
 
-void pose_adds_vgroups(struct Object *meshobj);
+void pose_adds_vgroups(struct Object *meshobj, int heatweights);
 
 void pose_calculate_path(struct Object *ob);
 void pose_clear_paths(struct Object *ob);