Adds a new widget to the rollout system.
        
        :param      widget      | <QWidget>
                    title       | <str>
                    expanded    | <bool>
        
        :return     <XRolloutItem>

def addRollout( self, widget, title, expanded = False ):
        """
        Adds a new widget to the rollout system.
        
        :param      widget      | <QWidget>
                    title       | <str>
                    expanded    | <bool>
        
        :return     <XRolloutItem>
        """
        layout = self.widget().layout()
        item = XRolloutItem(self, widget, title, expanded)
        layout.insertWidget(layout.count() - 1, item)
        return item