Redirect GET requests for pages w/o oldid to oldid location

 * Redirects requests for the latest version of an existing page to the
   proper ?oldid=12345 URL to hit the cached version.

 * Adds no-cache if wt is passed in.

 * Adds a favicon.

Bug: 56283
Change-Id: I527772e693334ed7efa5f013f690d882c134dbe4