Don't set an initial null root password for Amazon / VirtualBox images

A null password allows logging into local PAM services such as "login"
(agetty) and KDM.  That's not actually a security problem for EC2
machines, since they do not have "local" logins; for VirtualBox
machines, if you local access, you can do anything anyway.  But it's
better to be on the safe side and disable password-based logins for
root.
Print a reminder to users to set or disable the root password
Remove EOL'd kernels

Signed-off-by: Shea Levy <shea@shealevy.com>
Update default kernel to 3.10

Signed-off-by: Shea Levy <shea@shealevy.com>
Fold efi booting into the default livecd

Signed-off-by: Shea Levy <shea@shealevy.com>
ikiwiki: update to version 3.20130904
Include the NixOS version in the manual

In particular, this will make it clear what version of the manual is
shown at http://nixos.org/nixos/manual/.
haskell-git-annex: update to version 4.20131101