code: function mxPartitionLayout(graph, horizontal, spacing, border)
  {
  	mxGraphLayout.call(this, graph);
  	this.horizontal = (horizontal != null) ? horizontal : true;
  	this.spacing = spacing || 0;
  	this.border = border || 0;
  }
docs: Copyright (c) 2006-2015, JGraph Ltd
  Copyright (c) 2006-2015, Gaudenz Alder
   
  Class: mxPartitionLayout
  
  Extends <mxGraphLayout> for partitioning the parent cell vertically or
  horizontally by filling the complete area with the child cells. A horizontal
  layout partitions the height of the given parent whereas a a non-horizontal
  layout partitions the width. If the parent is a layer (that is, a child of
  the root node), then the current graph size is partitioned. The children do
  not need to be connected for this layout to work.
  
  Example:
  
  (code)
  var layout = new mxPartitionLayout(graph, true, 10, 20);
  layout.execute(graph.getDefaultParent());
  (end)
  
  Constructor: mxPartitionLayout
  
  Constructs a new stack layout layout for the specified graph,
  spacing, orientation and offset.