Include Font Awesome 4.2.0 (latest stable)

Downloaded from http://fortawesome.github.io/Font-Awesome/ .
Use webpack to load Font Awesome (not working)

There are many examples of this webpack config:

- https://www.npmjs.org/package/font-awesome-webpack
- https://github.com/bline/bootstrap-webpack
- https://github.com/aaronj1335/irked/blob/master/webpack.config.js

It's not working here though. The test icon added to `src/app.es6.js`
isn't showing, and the Chrome dev console shows errors for these
requests:

GET http://localhost:8080/d95d6f5d5ab7cfefd09651800b69bd54.woffv=4.2.0
GET http://localhost:8080/c4668ed2440df82d3fd2f8be9d31d07d.ttfv=4.2.0
GET http://localhost:8080/65bcbc899f379216109acd0b6c494618.svgv=4.2.0
Revert "Use webpack to load Font Awesome (not working)"

This reverts commit 7da4f2f17914a56f5ea5fb4c7df0489163a99f7f.
Load Font Awesome with <link> tag

Since couldn't get it to load through webpack (7da4f2f).
Use Font Awesome for correct and incorrect icons
Merge branch 'icons'