title: how to remove "powered by zingchart" in angularjs piechart
body: <p>Is there any way to remove "powered by zingchart" text in zingchart piechart ?</p>
  
  <p>I saw some answers in web, that need to add license key.</p>
  
  <p>Do we have any other way, without adding the license key ?</p>