Bug 1093219 - m3u parsing

There aren't any comments specifying what a song object is. I see here that it has a path and optionally a duration and some text. I assume that the text is an optional title or something.

Think about how the music app is going to use these playlists... When we're defining a new playlist in the app, is there ever any reason why we would want to specify a duration or text, or would it be enough to just pass the filename?  Alternatively, would it be easiest to have addSong() accept one of the fileinfo data structures (which include metadata) that MediaDB returns?