title: Fabric.js group coordinates with panned canvas
body: <p>I have a canvas that's initially panned so that the 0,0 point is in the middle of the screen. I'm trying to move a programmatically created group, but for some reason the group moves relative to the upper left corner of the visible canvas instead of the 0,0 point of the canvas. After that first movement the panning works correctly and the group moves around that position, until I discard it and create it again, and then it's relative to the upper left corner again, without taking the pan into account. If I create a group selection using the selection tool, it works correctly every time.</p>
  
  <p>I pan the canvas with this:</p>
  
  <pre><code>var offsetX = -canvas.getWidth()/2;
  var offsetY = -canvas.getHeight()/2;
  canvas.absolutePan(new fabric.Point(offsetX, offsetY));
  </code></pre>
  
  <p>This is how I create the group:</p>
  
  <pre><code>var group = new fabric.Group();
  objects.forEach(function (o) {
      group.addWithUpdate(o);
      canvas.remove(o);
  });
  canvas.add(group);
  </code></pre>
  
  <p>Then I try to move it with this:</p>
  
  <pre><code>group.set("left", 0);
  canvas.renderAll();
  </code></pre>
  
  <p>And then the group is right at the left edge of the canvas element. But if I select the group with my mouse and use this instead, it appears right where it should be - in the center:</p>
  
  <pre><code>canvas.getActiveGroup().set("left", 0);
  canvas.renderAll();
  </code></pre>
  
  <p>So, how do I get this to work properly? I know I could just calculate an offset from the canvas transformations, but I feel like this should be compensated for in the library itself and I'm either somehow using it wrong or it's a bug.</p>