/**
  * Constructor
  * 
  * @param string $username
  * @param string $password
  */
 public function __construct($username = '', $password = '')
 {
     parent::__construct();
     
     // If login credentials are not supplied, use the defaults stored in the config file
     
     require_once dirname(dirname(__FILE__)).'/Config.class.php';
     
     $config = new Config();
     
     if (!empty($username)) {
         $this->_username = $username;
     }
     else {
         $this->_username = $config->username;
     }
     
     if (!empty($password)) {
         $this->_password = $password;
     }
     else {
         $this->_password = $config->password;
     }
 }
 public function __construct()
 {
     parent::__construct();
 }