Automatically favorites a video on YouTube when you like it.
Version 1.1 now works on channels too.
Version 1.2 now shows a "Favorite" checkbox below the like button (checked by default).
Version 1.3 fixes channel support.
Version 1.4 makes the script work again.
Version 1.5 makes the script work with the new layout.
Version 1.6 makes the script work with the new layout.
