Add position to encoder msg payload

[fifi-reframe]

Hey there, I'm integrating a Phidget encoder (https://www.phidgets.com/?prodid=1199) into a Node-Red flow, and I'd love to be able to get the position from the payload. It appears that this is exposed in the Phidget API: https://www.phidgets.com/?view=api&product_id=1047_2. It would be really useful to have this to avoid integrating the positional changes myself :)

I was hoping to test this locally and open a PR, but not entirely sure how to do local testing. Ideally, a change would look something like

    encoder.onPositionChange = (positionChange, timeChange, indexTriggered) => {
      const msg = {
        topic: 'PositionChange',
        payload: {
          positionChange,
          timeChange,
          indexTriggered,
          position: encoder.position,
        },
      };
      node.send(msg);
    };

in phidget22-encoder.ts

Thanks in advance!