Autoupdate documentation with coqdoc to 4d6ede4

Generated with `make html` on commit:

commit 4d6ede4afc76c63a056c8ce7597720dcfdbbef13
Author: Jason Gross <jgross@mit.edu>
Date:   Fri Sep 27 19:35:02 2013 -0400

    Add the fact that whiskering is functorial