city.builders.xxx see as tuples

[littleneo]

register-builders branch :

city.builders.buildings.keys()
Traceback (most recent call last):
File "<blender_console>", line 1, in
AttributeError: 'tuple' object has no attribute 'keys'

your registration fails somewhere, this should be a collection. I will do some tests about pointer declared from outside / after class declarations, I'm pretty sure that's the point.
I suppose it does not work the way it does in normal python class mecanism, with that register() thing.

I'll update the wiki about my concept, things you don't get about the way it works. ( there's no bug about methods, as far as I know, in my branch ? )