code: function getDocking(point, referenceElement, moveAxis) {
  
    var referenceMid,
        inverseAxis;
  
    if (point.original) {
      return point.original;
    } else {
      referenceMid = getMid(referenceElement);
      inverseAxis = flipAxis(moveAxis);
  
      return axisSet(point, inverseAxis, referenceMid[inverseAxis]);
    }
  }
docs: Get the docking point on the given element.
  
  Compute a reasonable docking, if non exists.
  
  @param  {Point} point
  @param  {djs.model.Shape} referenceElement
  @param  {String} moveAxis (x|y)
  
  @return {Point}