code: function mxLabel(bounds, fill, stroke, strokewidth)
  {
  	mxRectangleShape.call(this, bounds, fill, stroke, strokewidth);
  }
docs: Copyright (c) 2006-2015, JGraph Ltd
  Copyright (c) 2006-2015, Gaudenz Alder
   
  Class: mxLabel
  
  Extends <mxShape> to implement an image shape with a label.
  This shape is registered under <mxConstants.SHAPE_LABEL> in
  <mxCellRenderer>.
  
  Constructor: mxLabel
  
  Constructs a new label shape.
  
  Parameters:
  
  bounds - <mxRectangle> that defines the bounds. This is stored in
  <mxShape.bounds>.
  fill - String that defines the fill color. This is stored in <fill>.
  stroke - String that defines the stroke color. This is stored in <stroke>.
  strokewidth - Optional integer that defines the stroke width. Default is
  1. This is stored in <strokewidth>.