- registering new python classes runs the free functions on existing classes.

- print an error if RNA Structs are freed with a python pointer set to help with debugging leaks.
- fix for unlikely eternal loop in unit conversion.

source/blender/python/intern/bpy_rna.h

@@ -83,4 +83,7 @@ PyObject *BPy_StringProperty(PyObject *self, PyObject *args, PyObject *kw);
 PyObject *pyrna_basetype_register(PyObject *self, PyObject *args);
 PyObject *pyrna_basetype_unregister(PyObject *self, PyObject *args);
 
+/* called before stopping python */
+void pyrna_free_types(void);
+
 #endif