This is not so weird. This new class does not contain *fav-td*, only *fav* so in the CSS-file, *.fav-td:before* has to be supplemented with *.fav:before* (comma-separated). However, you can skip modifying line 30 for now and just add the other modifications. I'll try to make a complete commit that consists of all the necessary changes for line 30 for the next time.
I assume I'll have to create a branch here on github first and then change all files in that branch before submitting a pull request.
Sorry for being a little premature here :)