The [downsides of icon fonts] are well-documented, and also, why ship all of the icons when it only uses 14? [downsides of icon fonts]: https://speakerdeck.com/ninjanails/death-to-icon-fonts
This is a pure git rename in order to make sure that git can follow history. The next commit will integrate these into mdbook-html. Additional commits will refactor/move/remove items.