Adding dovecot and postfix packages.
Adding discount, a Markdown->HTML processor in C.
Adding 9base-local, a full 9base installation in /local/plan9.
Enable kernel modules for iptables.
Adding the Go 1.2 compiler as a /local installation.
dovecot & postfix fixup

apparently logging of postfix doesnt work yet, but ultimately we
want it to use runit's logging, which requires the daemon running
in foreground and logging to stderr/stdout.