SELFISH: Prototype-based OOP

In order to conserve space, I neglected to let slots know their own
name(s). I need to either add a find-name function that will probe the dict
and discover the name of the slot (would have to look in parents, too), or
start storing the slot name with the slot (space-hog, and I'm not sure how
often code will need the name).

Another alternative would be to add a flag to setattr such that code that
needed the slot name could be explicitly added with the slot name. That
might be the best compromise. It would, of course, need to carry that flag
across object->object copies, so that it would always know what slot
name it was in if it originally requested such knowledge. Think about this.