Starts creating a new connection from the given output point.  \
        If a connection class is not provided, then the \
        defaultConnectionClass will be used.
        
        :param      point           <QPointF>
                    cls             subclass of <XNodeConnection>
                    output          <bool>

def startConnection( self, point, cls=None, output=True ):
        """
        Starts creating a new connection from the given output point.  \
        If a connection class is not provided, then the \
        defaultConnectionClass will be used.
        
        :param      point           <QPointF>
                    cls             subclass of <XNodeConnection>
                    output          <bool>
        """
        # clear the last connection
        self.finishConnection(False)
        
        # create a new connection
        self._activeConnection = self.addConnection(cls)
        if self._activeConnection:
            self._activeConnection.setOutputPoint(point)
            self._activeConnection.setInputPoint(point)
            self._activeConnection.setCustomData('__output__', output)
        
        return self._activeConnection