Another attempt to fix the installer test

http://hydra.nixos.org/build/9904133
Revert "slim: remove duplicate code"

This reverts commit f7d5e83abbe95ed06aac58f4d1a2e971fae4d186.  It
breaks the Firefox and Xfce tests:

  in job ‘tests.firefox.x86_64-linux’:
  cannot coerce a boolean to a string

  in job ‘tests.xfce.x86_64-linux’:
  infinite recursion encountered
nixos-hardware-scan: Detect QEMU
youtubeDL: update from 2014.03.25.1 to 2014.03.30.1
spaceFM: update from 0.9.2 to 0.9.4
perlPackages.HTMLTiny: update from 1.03 to 1.05
Ensure that slim's theme applies to slimlock
Bring back mkOrder