[Fedora-livecd-list] x86_64 support

[Brian Cain]

This tool is really great!  Thanks!

I've got a working x86_64 configuration.  I've also made some other
changes that I think make the livecd-creator script a little more
pythonic and added some little features that interested me.

I think I'd like to add support for multiple targets on the same CD at
some point, so I added in some abstractions that might facilitate
that.  I also made some tweaks to the exception handling.

Anyways, I've attached it here.  The changes to livecd-creator were
big enough that it didn't make enough sense to submit a patch.  If I
get a chance later I'll break the x86_64 support into its own patch.

I think I saw some messages about a git repository in the archives.
It wasn't mentioned on http://fedoraproject.org/wiki/FedoraLiveCD,
though.  Where's a good place to RTFM?
--
-Brian