Preparation of Playlist/EDL files support refactoring

git-svn-id: svn://svn.code.sf.net/p/mediainfo/code/MediaInfoLib/trunk@6579 45c5ae6f-87cc-4fd0-92ee-e4f023fd80da
Preparation of Playlist/EDL files support refactoring, update

git-svn-id: svn://svn.code.sf.net/p/mediainfo/code/MediaInfoLib/trunk@6580 45c5ae6f-87cc-4fd0-92ee-e4f023fd80da