Multiple bugfixes including namespace handling.

* The plugin now works correctly with Dokuwiki 2009-12-25.
* Correctly handle relative links like [otherpage] or
  [.:otherns:otherpage] when counting links.
* Cleanup debug code.
* Correct the regexps used to exclude <nowiki>, <code> and %%, replacing
  "*" with the non-greedy "*?" version.