- Added a brand-new access.module which allows you to manage 'roles'

  (groups) and 'permissions' ... (inspired by Zope's system).

    + Once installed, click the help-link for more information.

    + See updates/2.00-to-x.xx.sql for the SQL updates.

- Modified loads of code to use our new access.module.  The system
  still has to mature though: new permissions have to be added and
  existing permissions need stream-lining.  Awaiting suggestions.

- As a direct result of the new access system, I had to rewrite the
  way the top-level links in admin.php are rendered and displayed,
  and xhtml-ified admin.php while I was at it.

TODO

- Home-brewed modules need updating, home-brewed themes not.
  (Examples: file.module, trip_link.module)

- As soon we *finished* the refactoring of the user system (KJ has
  been working on this refactoring already) we should consider to
  embed this role and permission code into account.module ...