CT: try to download the best quality

For some movies, such as http://www.ceskatelevize.cz/ivysilani/
10362011008-ceske-stoleti/21251212023-velike-bourani-1918/, the first
quality in the list is the audio-desription version. This change tries
to sort the videos by quality (number in the label) and selects the best
one, ignoring the AD one.