Add a Type instance to the data model.

def addBaseType(self, item):
        '''
        Add a Type instance to the data model.
        '''
        ctor = '.'.join([item.__class__.__module__, item.__class__.__qualname__])
        self._modeldef['ctors'].append(((item.name, ctor, dict(item.opts), dict(item.info))))
        self.types[item.name] = item