make module.export both export factory & class

Hey, I really like the change in  https://github.com/argo/medea/commit/935670c46e1c4cace527b2a4b19957268e553ab6, but at the same time i can see reasons not to limit it so that the base class isn't available (if for example someone would like to extend the base class).

This change makes both of the initilizing patterns avaialble, from the same exported method.