Nix expressions.

  To subscribe to a channel (needs to be done only once):

    nix-channel --add \
      http://catamaran.labs.cs.uu.nl/dist/nix/channels/nixpkgs-unstable

  This just adds the given URL to ~/.nix-channels (which can also be
  edited manually).

  To update from all channels:

    nix-channel --update

  This fetches the latest expressions and pulls cache manifests.  The
  default Nix expression (~/.nix-defexpr) is made to point to the
  conjunction of the expressions downloaded from all channels.

  So to update all installed derivations in the current user
  environment:

    nix-channel --update
    nix-env --upgrade '*'

  If you are really courageous, you can put this in a cronjob or
  something.

  You can subscribe to multiple channels.  It is not entirely clear
  what happens when there are name clashes between derivations from
  different channels.  From nix-env/main.cc it appears that the one
  with the lowest (highest?) hash will be used, which is pretty
  meaningless.

  environment variable.  This is useful for passing authentication
  information (it won't show up in `ps').  Hacky - nix-push should
  abstract over the use of Curl.

* Made the dependencies on bzip2 and the shell explicit.

  Otherwise the substitute mechanism can break in subtle ways.

* nix-pull now requires the full url to the manifest, i.e.,
  `/MANIFEST/' is no longer automatically appended.
* nix-prefetch-url works again.  

  default -> default-94-link
  default-82-link -> /nix/store/cc4480...
  default-83-link -> /nix/store/caeec8...
  ...
  default-94-link -> /nix/store/2896ca...
  experimental -> experimental-2-link
  experimental-1-link -> /nix/store/cc4480...
  experimental-2-link -> /nix/store/a3148f...

* `--profile' / `-p' -> `--switch-profile' / `-S'
* `--link' / `-l' -> `--profile' / `-p'
* The default profile is stored in $prefix/var/nix/profiles.
  $prefix/var/nix/links is gone.  Profiles can be stored anywhere.
* The current profile is now referenced from ~/.nix-profile, not
  ~/.nix-userenv.
* The roots to the garbage collector now have extension `.gcroot', not
  `.id'.

* Use curl instead of wget.

  files.  Target location is no longer hard-coded; it accepts a number
  of URLs on the command line.

* `nix-install-package': compatibility fixes.

  the symlink ~/.nix-userenv to the given argument (which defaults to
  .../links/current).  /etc/profile.d/nix-profile creates this symlink
  if it doesn't exist yet.  Example use:

  $ nix-env -l my_profile -i foo.nix subversion quake
  $ nix-env -p my_profile

  I don't like the term "profile".  Let's deprecate it :-)

* Respect DESTDIR variable.

  --register-[substitutes|successors].

$ nix-instantiate --help
error: unknown flag `--help`
Try `nix-instantiate --help' for more information.

:-)

  "i686-linux" instead of "i686-suse-linux").

  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/.

  deleting a path in the store.
* Allow absolute paths in Nix expressions.
* Get nix-prefetch-url to work again.
* Various other fixes.

* Fixed a segfault caused by the buffering of stderr.
* Fix now allows the specification of the full output path.  This
  should be used with great care, since it by-passes the normal hash
  generation.
* Incremented the version number to 0.4 (prerelease).

* Fixed svn:ignore on externals/.

  override.

  fstate -> Nix expression).
* Fix src/test.cc.

* nar.sh needs a path.