Document interfaces an object implements/adapts

[jamadden]

I'm wondering if it would be possible to modify the output of the :class: directive for regular classes to (optionally?) show (and link) the interfaces the class implements and (if appropriate) the objects it adapts. This would look similar to the way the class's base classes can be linked.

This would be tremendously helpful in reducing the amount of boilerplate doc strings that just say something like "See foo.bar.IThing." It would also help in exploring the system as a whole.