Remove .eot & .ttf fonts

No issue

According to [caniuse](http://caniuse.com/#feat=woff), all the browsers we support (last 2 versions of major browsers) support the `.woff` font format. It's actually what pretty much all browsers will serve if its offered anyway.

This PR removes the `.eot` and `.ttf` font formats.

SVG remains as its the base file we use to add new icons & convert into other formats. It is not referenced anywhere.