udev: complete rework

- systemd puts all into one output now (except for man),
  because I wasn't able to fix all systemd/udev refernces
  for NixOS to work well
- libudev is now by default *copied* into another path,
  which is what most packages will use as build input :-)
- pkgs.udev = [ libudev.out libudev.dev ]; because there are too many
  references that just put `udev` into build inputs (to rewrite them all),
  also this made "${udev}/foo" fail at *evaluation* time
  so it's easier to catch and change to something more specific

pkgs/applications/editors/lighttable/default.nix

@@ -1,6 +1,6 @@
 { stdenv, fetchurl, buildEnv, makeDesktopItem, makeWrapper, zlib, glib, alsaLib
 , dbus, gtk, atk, pango, freetype, fontconfig, libgnome_keyring3, gdk_pixbuf
-, cairo, cups, expat, libgpgerror, nspr, gnome3, nss, xorg, udev
+, cairo, cups, expat, libgpgerror, nspr, gnome3, nss, xorg, libudev
 }:
 
 let
@@ -44,7 +44,7 @@ stdenv.mkDerivation rec {
       --set-rpath ${libPath}:${stdenv.cc.cc}/lib${stdenv.lib.optionalString stdenv.is64bit "64"} \
       $out/LightTable/ltbin
 
-    ln -sf ${udev.libudev}/lib/libudev.so.1 $out/LightTable/libudev.so.0
+    ln -sf ${libudev.out}/lib/libudev.so.1 $out/LightTable/libudev.so.0
 
     makeWrapper $out/LightTable/ltbin $out/bin/lighttable \
       --prefix "LD_LIBRARY_PATH" : $out/LightTable