title: Dynamic update of multiple series in highcharts
body: <p>I have a <code>highcharts-chart</code> with four lines (<code>series</code>).
  I would like to update each series with one point (<code>value</code>) and shift these four lines dynamically (1 in - 1 out) at the same time.
  This works with one series in the chart perfectly:</p>
  
  <pre><code>chart.series[0].addPoint([x, 5], true, true);
  </code></pre>
  
  <p>Is there a fast way to add the point to all four lines at once?</p>
  
  <p>Hanspeter</p>