revision: reverted the `when` form, but left a revision to this statement. 

This might be kind of hacky, but, if you specify a `page-ext` of  `/`, then the template thinks that everything ends in a slash, and coleslaw just puts an .html extension. Then you can tell your web server to drop the extensions seamlessly, and everything works perfectly. The old behavior is preserved, and with one if form (and some web server config) ayou can get pretty urls with minimal change.