WIP: Replace platform .png images with FontAwesome icons [OPEN-329]

https://s3.amazonaws.com/uploads.hipchat.com/26537/322375/bjvKhw7K8bgxiLk/Font%20Awesome%20Static%20Icon%20Reference.pdf
You'll want to add aria-hidden to this:
```<i class="icon icon-home" aria-hidden="true"></i>``` 
Some screen readers, like Voiceover on MAC and those used by people with cognitive disabilities, visually display what the screen reader is speaking, and even though FontAwesome uses private use areas, a visual glyph (not the icon) will still be rendered by the screen reader.  This fixes that.