Remove torbutton, rename torbutton-alpha to torbutton
Torbutton 1.4.0 is now the new stable torbutton. There is no alpha currently.
Torbutton 1.4.0's translations exist in the torbutton-alpha repository on transifex. We probably should archive what is in torbutton somehow, and then rename what is in torbutton-alpha to torbutton, so our translators are more aware of what needs translation for the current stable release.