title: how to add columns programmatically and set grouping on advancedDataGrid control in flex?
body: <p>on advancedDataGridControl in flex3 , how to do the following:</p>
  
  <p><strong>1.</strong> Add Columns at runtime ( programmatically )<br>
  <strong>2.</strong> Specify the column grouping ( programmatically )<br>
  <strong>3.</strong> set method to be used to show summary row ( programmatically)  </p>