Autoupdate documentation with coqdoc to 131cfcf

Generated with `make html` on commit:

commit 131cfcf2da5791574cc0001bc613fd418bc81eca
Author: Jason Gross <jgross@mit.edu>
Date:   Tue Sep 3 20:01:56 2013 -0400

    WIP coercion Functor >-> Pseudofunctor