- overhauled search system

- updated structure for search backend plugins
  - better result caching using ACM
  - search results no longer session restricted => link to them by copying the URL :)
  - in-topic search
  - indexing posts now uses search backend plugins
  - develop/search_fill.php working again
  - fulltext_mysql not working yet
- tiny bugfixes to ACM


git-svn-id: file:///svn/phpbb/trunk@5441 89ea8834-ac86-4346-8a33-228a782c2dd0

phpBB/includes/functions.php

@@ -2057,6 +2057,11 @@ function page_footer()
 			// Tidy some table rows every week
 			$cron_type = 'tidy_database';
 		}
+		else if (time() - $config['search_last_gc'] > $config['search_gc'])
+		{
+			// Tidy the cache
+			$cron_type = 'tidy_search';
+		}
 /**
 * @todo add session garbage collection