* One-click installation :-)

  The script nix-install-package takes a `Nix package file' (which
  contains one or more derivations, along with URLs of Nix caches),
  unpacks it, pulls the caches, and installs the derivations in the
  user's environment.

  For best results, associate the command `xterm -e
  /nix/bin/nix-install-package' with the MIME type
  `application/x-nix-package' and visit
  http://losser.st-lab.cs.uu.nl/~eelco/test/.