Set the domain name of the machine

The domain name was not being set before, even if the administrator
properly configured the networking.domain option in
/etc/nixos/configuration.nix.
transmission: Add apparmor profile
transmission: Add apparmor service dependency
Merge pull request #167 from wizeman/domain

Set the domain name of the machine
atd: don't enable at daemon by default

The at daemon doesn't work on NixOS [1], so enabling it by default
doesn't seem useful. I'd argue that it shouldn't be enabled by default
even if it worked, actually.

[1] http://lists.science.uu.nl/pipermail/nix-dev/2013-April/011048.html
Adding iw to systemPackages.
lighttpd: add cgit sub-service

(cgit is "a hyperfast web frontend for git repositories written in C")

cgit is enabled like this (assuming lighttpd is already enabled):

  services.lighttpd.cgit.enable = true;

and configured verbatim like this (contents of the cgitrc file):

  services.lighttpd.cgit.configText = ''
    cache-size=1000
    scan-path=/srv/git
  '';

cgit will be available from this URL: http://yourserver/cgit

In lighttpd, I've ensured that the cache dir for cgit is created if cgit
is enabled.
lighttpd: gitweb: add extraConfig option

So that we can append custom configuration text to the end of the
generated gitweb.conf file.
Merge pull request #179 from bjornfor/lighttpd-gitweb-improvements

lighttpd: gitweb: add extraConfig option
Merge pull request #178 from bjornfor/lighttpd-cgit-subservice

lighttpd: add cgit sub-service
Fixed disnix service to use systemd's dependency facilities
openvpn: fix type error

either use
- optional cond "target"
or
- optionals cond ["target1" "target2"]
TOR: add obfsproxy support by default for TOR bridges
Merge pull request #174 from wizeman/apparmor-transmission

transmission: Add apparmor profile
Omit GRUB if boot.loader.grub.device is set to "nodev"

If we only need to generate a GRUB boot menu, we don't need GRUB
itself.  This cuts 38 MiB from EC2 system closures (in particular
because it gets rid of the need for the 32-bit Glibc).
nixos-rebuild: Handle .version-suffix not being writable

Reported by @vcunat.
Merge branch 'master' into x-updates