I used to use Firegestures, and this was the most promising replacement after the big addon/extension change.

Gesturefy has been working fantastically, and I've even started using a couple more handy moves (like "Save Page As PDF" instead of printing as pdf for a very compact/neatly done pdf save, now I just need to find an addon that saves all open tabs as pdfs!).

Thanks Rob and Itch!