code: function(graph, action, flags) {
          var filter = this.filter(flags);
          for(var i in graph.nodes) {
            if(filter(graph.nodes[i])) action(graph.nodes[i]);
          } 
      }
docs: /*
  Method: eachNode
  
  Iterates over <Graph> nodes performing an *action*.
  
  Also implemented by:
  
  <Graph>.
  
  Parameters:
  
  graph - (object) A <Graph> instance.
  action - (function) A callback function having a <Graph.Node> as first formal parameter.
  
  Example:
  (start code js)
  $jit.Graph.Util.eachNode(graph, function(node) {
  alert(node.name);
  });
  or...
  graph.eachNode(function(node) {
  alert(node.name);
  });
  (end code)