DB_NestedSet output driver

Hi, Currently the output factory wants the driver to exists in the directory structure of DB_NestedSet (that is under DB/NestedSet/driver.php). I'd prefer the factory method to be like PEAR::Log which tries to instantiate the class even if it cannot include the file. It is useful when you want the driver you write not being in the pear directory structure, when you pout the application on a machine you have to remember to put the custom driver in the right place. As a side note the code should also be changed to be php5 compatible from

    function &factory ($params, $driver = 'TreeMenu') {
        return new $driverClass($params);

to

    function &factory ($params, $driver = 'TreeMenu') {
        $c =& new $driverClass($params);
        return $c;

Arnaud.