Patch D133: Python wrapper for BLI_kdtree (adds mathutils.kdtree)

Originally by Dan Eicher, with my own fixes and adjustments (see patch page for details).

For details there are unit tests and api example usage.

	doc/python_api/sphinx-in-tmp/menu_id.png

source/blender/python/mathutils/mathutils.h

@@ -58,6 +58,7 @@ typedef struct {
 /* utility submodules */
 #include "mathutils_geometry.h"
 #include "mathutils_noise.h"
+#include "mathutils_kdtree.h"
 
 PyObject *BaseMathObject_owner_get(BaseMathObject *self, void *);
 PyObject *BaseMathObject_is_wrapped_get(BaseMathObject *self, void *);