Trim fonts flavors to TTF/OTF only
Created by: xavierba
Nowadays, TTF and OTF font formats are supported in all browsers: https://caniuse.com/#search=ttf
Subsequently, there's no need to clutter the distribution with font flavors that won't be used anyway. Removing all but the TTF/OTF flavors for Font-Awesome and Foundation-Icons saves 350+KB.
Please note this change is unlikely to break any browser, as the third font shipped with Sympa, Raleway, is only distributed in the OTF flavor (and was only shipped in TTF flavor before #191).
The third commit is a fix to correct Raleway font format in default css. This supposedly minor bug, as it went unnoticed for more than a year, was introduced in #191.