Refactor to use fonts from bower

Rather than commiting the fonts in this repo, I think this repo should be refactored to include the fonts from a bower package whose purpose is to keep up to date with the material design icons.

I followed johnotander's guide to convert this add on to use the mdi bower package.

The only issue I saw was there isn't a chat icon(from read me examples), but I'm not sure if mdi' icons are older or if this icon was removed or this repo is tracking a different material design inspired icons.

FWIW, I don't see 'chat' on https://materialdesignicons.com

Start by reviewing the committed fonts and the add-on's dependency setup, then compare it with johnotander's guide and the mdi Bower package. Verify the README examples, especially the chat icon, against materialdesignicons.com; done means the fonts are no longer committed and the examples accurately reflect the supported icons.

Written by the indexing model from the issue text.