Apologies

[Gabriel Gonzalez]

I want to apologize to wren (and everybody else).  I was tired and 
overreacted when the discussion started veering into making more 
breaking changes.

I don't mind the Foldable changes too much.  My main concerns are:

* loss of monomorphism makes teaching more difficult
* They can be generalized in other useful ways

However, I don't consider those concerns show-stoppers.