Search engine redesign, first part :

- new table #search to store search rules associated to a search id.

- search rules are not passed through GET anymore, the search array build in
  search.php is serialized in #search table, so no need to rebuild it in
  function include/functions_category.inc.php::category_initialize

- search array build code is improved (efficiency and layout) in search.php

- SQL related to search is build in a dedicated function
  include/functions::get_sql_search_clause

- direct search author:<...>, date_avalaible:<...>, date_creation:<...>,
  keywords:<...> from picture.php are not available anymore. They will come
  back later, with improvement (new design). Same for date_*:<> in calendar
  calendar category.


git-svn-id: http://piwigo.org/svn/trunk@1008 68402e56-0260-453c-a942-63ccdbb3a9ee

install/phpwebgallery_structure.sql

@@ -176,6 +176,18 @@ CREATE TABLE `phpwebgallery_rate` (
   PRIMARY KEY  (`user_id`,`element_id`)
 ) TYPE=MyISAM;
 
+--
+-- Table structure for table `phpwebgallery_search`
+--
+
+DROP TABLE IF EXISTS `phpwebgallery_search`;
+CREATE TABLE `phpwebgallery_search` (
+  `id` int(10) unsigned NOT NULL auto_increment,
+  `last_seen` date default NULL,
+  `rules` text,
+  PRIMARY KEY  (`id`)
+) TYPE=MyISAM;
+
 --
 -- Table structure for table `phpwebgallery_sessions`
 --