title: How to change value for checkcolumn in grid
body: <p>I got grid with columns:</p>
  
  <p>...</p>
  
  <pre><code>    columns: [
          {
          xtype: 'rownumberer'
      }, {
          xtype: 'checkcolumn',
          sortable: false,
          header: 'done',
          dataIndex: 'status',
          flex: 2,
          width: 55,
          callback: function(success, model) {
              this.setRawValue(success); // DOESNT WORK
  this.setValue(success); // DOESNT WORK
          },
  }
  ...
  </code></pre>
  
  <p>I would like to change checkbox state to checked or unchecked. Functions setValue() or setRawValue() have no effect for the checkbox - moreover - there are not available for
  the widget.</p>
  
  <p>Is there simple function like setChecked(boolean) in extjs for checkcolumn?</p>
  
  <p>It is ridiculous I have instance 'checkcolumn' but I can't find basic function.</p>
  
  <p>I will be glad for any hint. Thank you.</p>
  
  <p>Bogus</p>