[plt-scheme] The new PLaneT server is online

I've just made a major upgrade to the server portion of PLaneT, PLT
Scheme's centralized package distribution system. Go to PLaneT's web
site:

   http://planet.plt-scheme.org/

and if the new DNS information has propagated to you, you'll see
several improvements. Here are some highlights:

* Package authors can now submit packages online directly, rather than
  having to send packages over email. If you have submitted a package
  to PLaneT before, you already have an account; just log in for the
  first time by clicking the "I forgot my password" link on the login
  page to reset your password so you can get in. (Even people who set
  their password during testing will have to do so again.)

* Authors can also edit their packages' metadata online.

* Package information now includes a release-notes field so that
  authors can include a description of the newest changes. Release
  notes are displayed on the PLaneT web page as well as in package
  announcement emails and the "newest packages" RSS feed. (See
  the documentation in help desk for more information.)

* Each package now has its own page, loaded with new information that
  wasn't available on PLaneT before. It includes:
    - The package description, release notes, sample require line, and
        docs link
    - A listing of provided names of all primary interface files,
        along with their contracts if available
    - Download statistics! (We have actually been keeping download
        statistics since the beginning of PLaneT, but the information
        has never been displayed on the web page before, so the
        download statistics online reflect the actual total downloads
        of each package since it was uploaded)
    - Browsable source code (thanks to Jens Axel Soegaard)
    - Historical release information

* Each user now has a listings page as well, so you can easily link to
  all of your packages. User and package pages are available using
  friendly links:
    http://planet.plt-scheme.org/users/dherman/
    http://planet.plt-scheme.org/users/dherman/io.plt/

* Many many smaller improvements

The server-side change should be totally transparent to clients, so as
soon as the new DNS information propagates to you, your PLaneT client
should start using the new server automatically. There are a few
caveats, though:

* The very old, non-HTTP protocol that worked over port 270 is no
  longer supported. This should only affect people who have
  specifically configured their PLaneT clients to use the non-HTTP
  protocol, or users of very old versions of PLT Scheme in the 20x
  series.

* PLaneT is no longer accepting packages for the 20x repository,
  though these packages are still available to 20x clients.

* A general note: this is essentially a complete reimplementation of
  the PLaneT server, so you may encounter bugs or problems. If you do,
  please let me know!

Have fun with the new features, and I'd love to hear any feedback
you've got.

-jacob