[Nix-dev] mongodb, ghc-mod, youtube-dl and a bunch of upgrades

[Mathijs Kwik]

Hi all,

I created a few new packages and upgrades existing ones.
Can someone with commit access please review my commits and apply them to svn?

[1] nixpkg additions/changes
[2] nixos module for mongodb
[3] nixpkg changes (on top of 1) that might need some discussion

[1] https://github.com/bluescreen303/nixpkgs/commits/pull-request
[2] https://github.com/bluescreen303/nixos/commits/pull-request
[3] https://github.com/bluescreen303/nixpkgs/commits/controversial-discuss-first

All comments are very welcome, as I'm still learning nix stuff.

Thanks,
Mathijs