qt48: bugfix update 4.8.5 -> .6

Some patches dropped, as they seemed included.
Remove use of obsolete flags
Bring back the isSystemUser option
Allocate system uids/gids between 400 and 500

Previously it was between 100 and 500, but this can already collide
with the static uids/guid in misc/ids.nix.
Fix some uid/gid attributes to match the actual user/group name
nixos: Add support for changing supported systems

release.nix and release-combined.nix current hardcode the systems which
they are built for. This change introduces an argument to the
expressions called supportedSystems, which allows the builder to choose
which architectures he wants to build. By default, this uses the same
linux x86_64 and i686 architectures.
Let users install fonts to their HOME directory
Remove redundant ~/.fonts element from the font search path
Shut up warning about missing fonts.dtd
Obsolete fonts.extraFonts

You can now just set fonts.fonts, which will be merged with the
default value unless you use mkOverride.
Update haskell-http-kit to version 0.2.2
Rename hardware.opengl.videoDrivers back to services.xserver.videoDrivers

Fixes #2379.
The new name was a misnomer because the values really are X11 video
drivers (e.g. ‘cirrus’ or ‘nvidia’), not OpenGL implementations. That
it's also used to set an OpenGL implementation for kmscon is just
confusing overloading.
Move the NVIDIA support into its own module

Previously all card-specific stuff was scattered across xserver.nix
and opengl.nix, which is ugly. Now it can be kept together in a single
card-specific module. This required the addition of a few internal
options:

- services.xserver.drivers: A list of { name, driverName, modules,
  libPath } sets.

- hardware.opengl.package: The OpenGL implementation. Note that there
  can be only one OpenGL implementation at a time in a system
  configuration (i.e. no dynamic detection).

- hardware.opengl.package32: The 32-bit OpenGL implementation.
Xfce: Don't depend on GTK+ 3 by default

Given that Xfce is intended as a light-weight desktop environment,
pulling in two versions of GTK+ by default is not ideal.
Merge pull request #2444 from sol/update-http-kit

Update haskell-http-kit to version 0.2.2
Add a test for automounting
Disable autofs module

It appears to be unmaintained and untested. Also, systemd provides
automount functionality so it's probably not needed anymore.
tzdata: fix 'posix' symlink
tzdata: Update to 2014b
tzdata: use symlinks instead of hardlinks

Hard links are not handled by nar, so installing from binary cache
unnecessarily duplicates data. Also, it's more common to use symlinks for the
tzdata package in other distributions.