Journey

Backports the router from rails master.

This mostly involved copy/pasting from `ActionDispatch::Routing` in rails4 to `ActionController::Routing` in rails2.3. I made a bunch of tweaks to support ruby 1.8, integrate with the rails2.3 request and integration stacks, etc.

Also includes a version of DeprecatedMapper that works with journey, so you can use existing rails2.3 style routes files with the new router.