Blender Git Loki

* Fix crash in the getParent() and getTracked() methods of the Python API.
This crash was reported by Jean-Michel Soler (jms).
Problem was that I was trying to be a little too intelligent. I kept a
reference to created PyObjects which at some point apparently fails. Keeping
the object references is not necessary. Now we just create a new PyObject
when necessary and let Python handle the reference counts.