Add fancier URL redirects #294

We have some basic URL redirects in this file: https://github.com/mapzen/documentation/blob/master/setup-redirects.py

It would be great to get better redirects, including allowing anchor links in the forwarded URL. That does not seem to work currently (it just goes to the top of the page).

We have attempted to contribute our redirect code to the source mkdocs, but there was not interest in this functionality.