Still trying to make fonts work

As pointed out by
http://stackoverflow.com/questions/940451/using-relative-url-in-css-file-what-location-is-it-relative-to
the URL for fonts is relative to the stylesheet. However, since the asset
pipeline compiles everything into a single stylesheet, that means that the URLs
need to point to the /assets directory. At least that's my current theory. Let's
see if this works...