KeyboardDragListener violates PhET convention for ES5 set/get, resulting in more differences with DragListener.

[pixelzoom]

Related to #1307 ...

KeyboardDragListener also deviates from DragListener in how it defines ES5 getters. KeyboardDragListener violates PhET convention and does not have non-ES5 set and get methods.

For example:

// KeyboardDragListener.js
  set transform( transform ) { this._transform = transform; }
  get transform() { return this._transform; }

// DragListener.js
  setTransform( transform ) {...}
  set transform( transform ) { this.setTransform( transform ); }

  getTransform() { 
    return this._transform;
  }
  get transform() { return this.getTransform(); }

This is one more thing to deal with when adding a KeyboardDragListener.

For example, in Geometric Optics, I had this in GORulerNode.js:

   zoomTransformProperty.link( zoomTransform => {
      this.dragListener.setTransform( zoomTransform );
    } );

I want to do the same for a KeyboardDragListener I'm adding to GORulerNode, so I naturally expect to be able to add it like this:

    zoomTransformProperty.link( zoomTransform => {
      this.dragListener.setTransform( zoomTransform );
      keyboardDragListener.setTransform( zoomTransform );
    } );

That fails, because there is no KeyboardDragListener setTransform. So I have to either live with the difference:

      this.dragListener.setTransform( zoomTransform );
      keyboardDragListener.transform = transform;
    } )

... or change working code so that they are the same:

      this.dragListener.transform = zoomTransform;
      keyboardDragListener.transform = transform;
    } )

[zepumph]

Sounds about right. I'll fix drag bounds over in #1307.

[zepumph]

I updated the API for transform in KeyboardDragListener above. I didn't see any other getters or setters needing work. @pixelzoom is there anything else here?

[pixelzoom]

Changes look good, and I see it's being used in geometric-optics. Closing, thanks!