code: function mxStackLayout(graph, horizontal, spacing, x0, y0, border)
  {
  	mxGraphLayout.call(this, graph);
  	this.horizontal = (horizontal != null) ? horizontal : true;
  	this.spacing = (spacing != null) ? spacing : 0;
  	this.x0 = (x0 != null) ? x0 : 0;
  	this.y0 = (y0 != null) ? y0 : 0;
  	this.border = (border != null) ? border : 0;
  }
docs: Copyright (c) 2006-2015, JGraph Ltd
  Copyright (c) 2006-2015, Gaudenz Alder
   
  Class: mxStackLayout
  
  Extends <mxGraphLayout> to create a horizontal or vertical stack of the
  child vertices. The children do not need to be connected for this layout
  to work.
  
  Example:
  
  (code)
  var layout = new mxStackLayout(graph, true);
  layout.execute(graph.getDefaultParent());
  (end)
  
  Constructor: mxStackLayout
  
  Constructs a new stack layout layout for the specified graph,
  spacing, orientation and offset.