Exppython:

- Fixed a problem with control of the global Python dictionary persistence:
    Blender.ReleaseGlobalDict(bool) should now work fine.
- Trying to fix the sigsegv crashes on Windows:
    They happen when we try to "print" our objects, like Lamps or Cameras.
    Following advice from the Python Embedding doc, removed the tp_print
    method from Camera and also improved its tp_repr one, that will be used
    as print, repr() and str() for Cameras.  If this test works all other objs
    will be updated accordingly.

source/blender/python/api2_2x/Material.c

@@ -167,6 +167,8 @@ static PyObject *M_Material_New(PyObject *self, PyObject *args,
     return (EXPP_ReturnPyObjError (PyExc_RuntimeError,
                             "couldn't create Material Data in Blender"));
 
+  blmat->id.us = 0; /* was incref'ed by add_material() above */
+
   if (pymat == NULL)
     return (EXPP_ReturnPyObjError (PyExc_MemoryError,
                             "couldn't create Material Data object"));