Support MPEG4 subtitle format
As requested in: http://forum.videolan.org/viewtopic.php?f=7&t=54203&p=178103#p178009
There are some media files, that use embedded QuickTime subtitles and these subtitles don't show up in VLC.
Sample file: http://diagonal.com/mp4/mikisballade_withsubs.m4v