fixed: thread plugin didn't correctly set the last item and replies (in 'thread' table)

when deleting an answer
added: ThreadInfo::Repair() method
       will be used by 'fsck' winix function       
added: plugins/groupitem 
       directory for a new plugin: 'groupitem'
       


git-svn-id: svn://ttmath.org/publicrep/winix/trunk@725 e52654a7-88a9-db11-a3e9-0013d4bc506e

db/dbitemquery.h

@@ -52,7 +52,8 @@ struct DbItemQuery
 	long offset;
 
 	DbItemQuery();
-	
+	void Clear();
+
 	void SetAllSel(bool sel);
 	void SetAllWhere(bool where_);
 	void SetAll(bool sel, bool where_);