updated Restore CD HOWTO page for 5.0_BETA

Hi,

I've updated NetBSD/cobalt Restore CD HOWTO page
for the newer 5.0_BETA restorecd script:

http://www.NetBSD.org/ports/cobalt/restorecd-howto.html

- update how-to-create section (using Makefile in the script)
- add a full "how to use" procedure
- add "Restore CD Internals" section for future developers

I've also upload updated the restorecd script and ISO image
based on netbsd-5/200811160002Z daily build snapshot:
ftp://ftp.NetBSD.org/pub/NetBSD/arch/cobalt/restore-cd/5.0_BETA/

Note now you can create your restorecd ISO image
even on Windows with Cygwin tools.

Enjoy,
---
Izumi Tsutsui