Added favicon
Added favicon

Added missing favicon [from bug 1029713](https://bugzilla.mozilla.org/show_bug.cgi?id=1029713)
alicoding/webmaker.org,mozilla/webmaker.org,cadecairos/webmaker.org,cadecairos/webmaker.org,mmmavis/webmaker.org,alicoding/webmaker.org,mmmavis/webmaker.org,mozilla/webmaker.org