- Removed left-overs from the rating module. Patch by Gerhard. Updated the

  PostgreSQL and MSSQL database scheme as well.

- Made sure the update script updates the correct tables when database
  prefixing is enabled.  Patch by Bart Jansens.

- Improved the breadcrumb navigation of the book and the forum module as per
  Keith Instone's suggestions.

- Updated page titles (or block titles) and links to match.  Suggested by
  Keith Instone.

- Added missing 'thread' field to the comment table of the MySQL database scheme.
  Fixes bug #2590.