- Patch by JonBob/Jonathan: reworked the menu system so that menus are

  configurable!  Menu items can be disabled, repositioned, added and
  so on.

  Upgrading to requires you to run update.php.

  This functionality depricates some of the 'navigation modules' in the
  contributions repository.  Furthermore, modules can now 'suggest'
  menu items and site adminstrators can choose to enable them.  Modules
  in the contributions repository should try to take advantage of this.