Grab the relative path instead of rebuilding it

For a request to `http://localhost:9393/font/fontello.woff`, `request.path_info`
is `/font/fontello.woff`, so we can just use that instaed of rebuilding it "by
hand".
Caching is more trouble than it is worth

Setting the `Cache-Control` header to `ONE_DAY` meant that it was being reset
every time a user visited the site. The goal was really to have the
`Cache-Control` set to "the end of today", rather than "one day from this
second".

That's easily implemented, but is honestly more trouble than it's worth, so I'm
just removing caching.