title: group members not centering in group
body: <p>I'm creating a simple group, with circle and text, and I expected the text to be centered over the circle. (Like in the group demo on the front page of fabricjs.com!)</p>
  
  <pre><code>var text = new fabric.Text('hello world', {
    fontSize: 30
  });
  
  var circle = new fabric.Circle({
    radius: 100,
    fill: '#eef',
  });
  
  var group = new fabric.Group([ circle, text ], {
    left: 150,
    top: 100,
    angle: -10
  });
  
  canvas.add(group);
  </code></pre>
  
  <p>I've in fact taken that from the beginning of the tutorial page on Groups, but removed the circle's scaleY to make the non-centering more obvious.</p>
  
  <p>I have a JSFiddle of it up, and tracing thorough the Fabric code I don't see anything that would actually center the contents; Group.prototype._updateObjectCoords just offsets by the group's position, making the contents' <code>top</code> and <code>left</code> simply be relative to the top-left of the group itself. And yet, it seems to work on the demo page!</p>
  
  <p><a href="http://jsfiddle.net/xGtvj/" rel="nofollow">http://jsfiddle.net/xGtvj/</a></p>