title: bar chart legend color change
body: <p>I would like to change the color of bar chart in extjs. 
  I can changing the bar with renderer in series, but now I would like to change the legend's color too.
  Here is the piece of code:</p>
  
  <pre><code>           .. series : [ {
                  type : 'bar',
                  axis : 'bottom',
                  gutter : 0,
                  groupGutter : 0,
                  yField : this.fields,
                  title : this.fieldTitles,
                  colorArrayStyle : ['#FFF']
                  stacked : true,
                  fill: true,
                  scope: this,
                  renderer: function(sprite, record, attr, index, store) {
                      var color = fieldColors[index];                    
                      attr.fill = color;
                      return attr;
                 }, ....
  </code></pre>
  
  <p>How can I change the legend's color? </p>