1. Add pulseaudio and xsreensaver support
2. Use default arguments instead of custom args in all-packages.nix.
3. Remove ? null. callPackage passes all these args anyway.
4. Add binary codecs for non-i686 platforms. Have no video to test.
5. Use fetchsvn instead of gentoo-made snapshot.
svn path=/nixpkgs/trunk/; revision=23285