title: highstock set tooltip text color
body: <p>In highstock chart I want to display my custom tooltip. It's text color should be same as color of first serie.</p>
  
  <p>How is it posiible to do?
  This does not work:</p>
  
  <pre><code>function CustomFormatter() {
    var s = "";
    var items = this.points;
    for (var i = items.length - 1; i &gt;= 0; --i) {
      s += items[i].point.name + ': ' + '&lt;b&gt;' + items[i].point.y + '&lt;/b&gt;' + '&lt;br&gt;';
    }
  
    return '&lt;span style="color: ' + options.colors[1] +'"&gt;'
         + Highcharts.dateFormat(' %a, %d %b %y', items[0].point.x)
         + '&lt;/span&gt;' + '&lt;br&gt;' + s;
  }
  </code></pre>
  
  <p>Thanks,
  Zhenya</p>