Module for CVE-2013-4164

So far, just a DoS. So far, just tested on recent Rails with Webrick and
Thin front ends -- would love to see some testing on ngix/apache with
passenger/mod_rails but I don't have it set up at the moment.
Add user-controlled verbs.

GET, HEAD, POST, and PROPFIND were tested on WebRick, all successful.
Remove timeout checkers that are rescued anyway
Land #2676, @todb-r7 module for CVE-2013-4164