Update Torbutton Transifex Docs
After doing the .po dance for torbutton with our new transifex setup, runa wants me to update the docs at: https://svn.torproject.org/svn/translation/trunk/documentation/howto.txt
After doing the .po dance for torbutton with our new transifex setup, runa wants me to update the docs at: https://svn.torproject.org/svn/translation/trunk/documentation/howto.txt