Drupal Installer

The SDF MOTD project already has two Drupal installers, but as these
are both for out-of-date versions of the software (versions 5.1 and
5.5 versus the current 6.19), and are more or less broken, I'm going
to contribute my own verson.

In addition to providing the latest Drupal version and fixing bugs in
the current install scripts, I hope to make the script capable of
gracefully adapting to future version releases, so that I or another
MOTD member can just download and unpack a new version tarball, and
update the description file to indicate the new version number. I
don't think the MOTD project needs to maintain every past version of
every package.