Message 232825 - Python tracker

* Macros could be useful.
* Would this make it easy/faster to also have a DefaultOrderedDict (which can/could also be accomplished with .get(attr, []) and .setdefault(attr, [])?
* There may be some value in looking at https://pypi.python.org/pypi/cyordereddict
* (I'm really not qualified to review this. Valgrind?)