[AD] textprintf_right bug

["Trent Gamblin" <tmg@xxxxxxxxxx>]

textprintf_right is just like textprintf_centre. To fix, change
line 276 in text.c from

textout_centre(bmp, f, buf, x, y, color);

to

textout(bmp, f, buf, x - text_length(f, buf), y, color);