iso9660/cdrom checkins

Hi folks,

I've checked in a working iso9660 fs module and a mostly complete 
(and working :), but messy cdrom session module.  I'm afraid I 
haven't been able to work on things much the past couple of days, and 
won't be able to do any more for at least a couple more.  

The cdrom module should be working for most cds; I need to clean 
things up quite a bit and handle a few special cases, though, before 
it will be complete.  Ingo and Axel, I'll reply to your recent 
postings as soon as I get a chance; sorry for the delay. :(

-Tyler