Yaocho APIs

This adds a few APIs that were useful for Yaocho. These need to get to prod before I can put Yaocho in the marketplace.

r?
This is a lot like the code in `kitsune/url/resolvers.py`. Part of me wonders whether we can reuse that code and/or rewrite it. It has similar issues in that we're doing transforms on static data every request just like this code does. But it also uses different forms of that static data that might be in a more useful form.