File paths in M3Us made by Cog

Thanks. I'll take a look when I get a chance.
Cog's playlists wont be compatible with other playlists any more if it contains multi-track files due to the way Cog keeps track of them (Most players don't treat them as individual files, to my knowledge).I don't see this as a huge problem, but with this relative path bug, it isn't even across-machine Cog compatible, so that definitely needs fixing.