title: Rotating a custom geometry mesh around its center point
body: <p>When we add a CustomGeometry to the scene with defining vertices and not setting the position, how can we get it to rotate around its own center point?</p>
  
  <p>Fiddle : http://jsfiddle.net/tezcancirakoglu/Ldt7z</p>
  
  <p>In the sample code, object is rotating around Scenes X axis. I need to rotate it around its center point.</p>
  
  <p>Hint: The red cube mesh is the initial centerpoint of the object which is rotating. I need to rotate it around x axis of red cube... I tried alot but failed anyway.</p>