[subtitles core] set correct icon
Merge pull request #3638 from Voyager1/fix-dvd-subs

[dvdplayer] Fix streams for DVDs sync with lang settings gui
[fix] play from here in a DVD container folder only queue main file instead of all files
CFileItem - factor out determination of optical media math
[fix] Playback of a DVD as files in a folder should not create a playlist of those files