Replace FontCustom

[connorshea]

At some point in the future (probably not a priority right now) we should replace fontcustom with something better. At the moment there's no development going on with the gem, and the way we're doing this artificially inflates the size of the CSS tremendously (not as much of a problem thanks to GZIP, but still).

Essentially, every single time we use @import "scss-variables"; we also import the styles for the icon font along with the variables we're actually trying to import, which means that the icon font styles are repeated more than a dozen times in the final compiled styles.

...whoops 😰