Made the variables dim_modules, dim_classes and dim_map class variables ...

...instead of being static variables

The problem was occurring while launching "manage.py all update".
In the "run_command" function from main.py, the static dim_modules, dim_classes and dim_map variables from MyFact were set up once for all during the first iteration, and never changed afterwards.

So, if let's say the 3rd fact has one dimension more than the 1st one, the dim_modules, dim_classes  and dim_map were still the one from the 1st fact, and not from the 3rd, hence the error.