changed: DirContainer - uses std::list instead of std::vector as the main container

we do not have to rebuild indexes after deleting some items
added:   DirContainer::DelById(long id)
changed: Dirs::CheckRootDir() addes the root dir if there is no one
added:   Dirs::DeleteDir(long id) - deletes specified directory (and its contents)
         (from the cache and the database)
added:   Db::DelDirById(long id) - deletes a dir from the database 
         and its first children
added:   standard function rm can delete directories


git-svn-id: svn://ttmath.org/publicrep/cmslu/trunk@487 e52654a7-88a9-db11-a3e9-0013d4bc506e

core/session.h

@@ -49,6 +49,8 @@ struct Session
 	Item item;
 
 
+	std::string dir_old;
+
 	// -------------------
 
 	Session();
@@ -57,6 +59,7 @@ struct Session
 	bool operator<(const Session & s) const;
 	bool DecTimer(int & timer);
 	void CheckTimers();
+	void IncrementTimersIfExist();
 };