title: Set enable/disable 3D mode with Highcharts
body: <p>I made a form to change values dinamically in my chart. I can change title, subtitle, etc, but... How can I change to set enabled or disabled 3D mode??</p>
  
  <pre><code>$(document).ready(function () {
  
      //Title inputText
      $('#gra_title').blur(function(){
          chart.setTitle({ text: $('#gra_title').attr("value") });
      });
  
      //Subtitle inputText
      $('#gra_subtitle').blur(function(){
          chart.setTitle(null, { text: $('#gra_subtitle').attr("value") });
      });
  
      //Credits checkbox
      $('#gra_credits_visible').click(function () {
          if ($('#gra_credits_visible').is(':checked')){ 
              chart.credits.show();
          }else{
              chart.credits.hide();
          }
      });
  
  .........  //More events to change chart
  
      //3D checkbox - MY PERSONAL BUG
      $('#gra_3d_visible').click(function () {
          if ($('#gra_3d_visible').is(':checked')){ 
              chart.options.chart.options3d.enabled = true;
          }else{
              chart.options.chart.options3d.enabled = false;
          }
          chart.redraw();
          // return TRUE or FALSE, but don't change 3D/2D mode
          alert(chart.options.chart.options3d.enabled);
      });
  
  
  });
  </code></pre>
  
  <p>This is my chart:</p>
  
  <pre><code>chart = new Highcharts.Chart({
      chart: {
          renderTo: 'container',
          marginRight: 0,
          events: {
              load: function () {
                  this.credits.element.onclick = function () {
                      window.open('http://www.url.com', '_blank');
                  }
              }
          },
          marginTop: 80,
          type: 'column',
          options3d: {
              enabled: true,
              alpha: 15,
              beta: 15,
              viewDistance: 25,
              depth: 90
          }
      },
      plotOptions: {
          column: {
              depth: 90
          }
      },
      credits: {
          enabled: true,
          text: 'MyWeb.com',
          style: {
              cursor: 'pointer',
              color: '#909090',
              fontSize: '10px'
          }
      },
      title: {
          text: 'Población Mundial'
      },
      subtitle: {
          text: 'Fuente: Wikipedia.org'
      },
      xAxis: {
          title: {
              text: 'Continentes'
          },
          categories: ['Africa', 'América', 'Asia', 'Europa', 'Oceanía']
      },
      yAxis: {
          title: {
              text: 'Población (millones)'
          },
      },
      series: [{
          name: 'Año 1800',
          data: [107, 31, 635, 203, 2]
      }]
  });
  </code></pre>
  
  <p>I've looking for in <a href="http://api.highcharts.com/highcharts" rel="nofollow">API Documentation</a> but I didn't find nothing.</p>