title: Highcharts: passing additional information to a tooltip
body: <p>I have an array of data points that I am passing to a Highcharts chart that looks like</p>
  
  <pre><code>mydata = [{
      x: 1,
      y: 3,
      nameList: ["name1", "name2"]
  }, {
      x: 2,
      y: 4,
      nameList: ["name3", "name4"]
  }]
  </code></pre>
  
  <p>I build the chart like this:</p>
  
  <pre><code>$("#chart").highcharts("StockChart", {
      series: [{
          data: mydata
      }, {
          data: yourdata
      }]
  });
  </code></pre>
  
  <p>Now, I would like to be able to access the nameList array from the shared tooltip, which I'm trying to do as follows:</p>
  
  <pre><code>tooltip: {
      formatter: function() {
          var s = "";
          $.each(this.points, function(i, point) {
              s += point.point.nameList;
          });
          return s;
      },
      shared: true
  }
  </code></pre>
  
  <p>but when examining the point objects in Firebug using <code>console.log(point)</code>, I can't seem to find the nameList entry anywhere in them. How could I access this auxiliary information in a shared series tooltip? All help is appreciated.</p>