TradeItem drill_down() method is outrageous

[jMyles]

I'll just let it speak for itself:

    def drill_down(self):
        """
        Stupid and hopefully temporary.  Some of the worst code of my life in this function here.

        TODO: Unstupify.

        See http://stackoverflow.com/questions/5348157/find-object-in-child-class-from-object-in-parent-class-in-django
        """
        try:             
            return self.moneybagpiece
        except:
            try:
                return self.realthing.ingredientstock
            except:
                try:
                    return self.realthing.device
                except:
                    return self.realthing

Obviously we can do better with django-model-utils.