Add a language code to the filename

[felagund]

Appends language code of the subtitle to the resulting filename. So instead of (typically) name_of_the_movie.srt, one gets name_of_the_movie_eng/fre/ger/etc.srt. This is useful when using this script with more then one language (now, if I download first English subtitles and then French subtitles, French subtitles rewrite English subtitles).

[emericg]

Thank you, commited ! I hope this will not cause extra problems with some old media players that could only load subtitles with the exact same name as the video...