Can proxy for save/load for the tracks for phetio.js be removed?

[jessegreenberg]

This block is in EnergySkateParkBasicsModel

    // Proxy for save/load for the tracks for phetio.js
    // TODO: This is all a bit hackish, to serialize the tracks.  Cannot this be made simpler?
    if ( draggableTracks ) {
      //phetio && phetio.addInstance( 'playgroundScreen.tracks', {
      //  phetioID: 'playgroundScreen.tracks',
      //
      //  // TODO: use get value instead of this function.
      //  getArray: function() {
      //  },
      //
      //  get value() {
      //    return this.getArray();
      //  },
      //
      //  // TODO: set value asymmetric from getArray
      //  set value( arrayOfArrayOfVector ) {

      //  }
      //} );
    }

Not sure if we still want this around. @samreid would you like to keep this commented code?

[jessegreenberg]

For #398.

[samreid]

It can be deleted now, thanks!

[jessegreenberg]

Deleted, closing.