title: Change title when drilldown in Highcharts
body: <p>I'm looking for a way to show a info text in Highcharts when using drilldowns. I want a text that tells my visitors that another chart has been showed up. A title for example:
  "New chart - more about Animals"</p>
  
  <p><a href="http://jsfiddle.net/6zYmJ/">http://jsfiddle.net/6zYmJ/</a></p>
  
  <p>Do you have any ideas how to do that?</p>
  
  <pre><code>$(function () {    
  
  // Create the chart
  $('#container').highcharts({
      chart: {
          type: 'column'
      },
      title: {
          text: 'Basic drilldown'
      },
      xAxis: {
          type: 'category'
      },
  
      legend: {
          enabled: false
      },
  
      plotOptions: {
          series: {
              borderWidth: 0,
              dataLabels: {
                  enabled: true,
              }
          }
      },
  
      series: [{
          name: 'Things',
          colorByPoint: true,
          data: [{
              name: 'Animals',
              y: 5,
              drilldown: 'animals'
          }, {
              name: 'Fruits',
              y: 2,
              drilldown: 'fruits'
          }, {
              name: 'Cars',
              y: 4,
              drilldown: 'cars'
          }]
      }, {
          name: 'Things',
          colorByPoint: true,
          data: [{
              name: 'Animals2',
              y: 5,
              drilldown: 'animals2'
          }, {
              name: 'Fruits2',
              y: 2,
              drilldown: 'fruits2'
          }, {
              name: 'Cars2',
              y: 4,
              drilldown: 'cars2'
          }]
      }],
      drilldown: {
          series: [{
              id: 'animals',
              data: [
                  ['Cats', 4],
                  ['Dogs', 2],
                  ['Cows', 1],
                  ['Sheep', 2],
                  ['Pigs', 1]
              ]
          }, {
              id: 'fruits',
              data: [
                  ['Apples', 4],
                  ['Oranges', 2]
              ]
          }, {
              id: 'cars',
              data: [
                  ['Toyota', 4],
                  ['Opel', 2],
                  ['Volkswagen', 2]
              ]
          },{
              id: 'animals2',
              data: [
                  ['Cats', 4],
                  ['Dogs', 2],
                  ['Cows', 1],
                  ['Sheep', 2],
                  ['Pigs', 1]
              ]
          }, {
              id: 'fruits2',
              data: [
                  ['Apples', 4],
                  ['Oranges', 2]
              ]
          }, {
              id: 'cars2',
              data: [
                  ['Toyota', 4],
                  ['Opel', 2],
                  ['Volkswagen', 2]
              ]
          }]
      }
  })
  });
  </code></pre>