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
The screen reader text here "Dashboard for " is a good alternative for what the icon conveys.  A small nit: get rid of the colon, which will be read by most screen readers e.g. dashboard for colon johnsmith