title: Fabric.js: cannot get bounding box to match it's (dynamic) object
body: <p>I am trying to give the user of a page the possibility to draw his/her own polygon onto an image. I use fabric.js (1.5.0) for that, and I borrowed quite some code from the examples there, however, in my case, the bounding boxes of the created polygons just don't match the polygons.
  FireBug shows the points of the polygons being rather local than global, what is in my believe the cause of the problem. I'm kind of lost though in finding the crucial lines...</p>
  
  <pre><code>See the jsfiddle below for my example
  </code></pre>
  
  <p><a href="https://jsfiddle.net/y9kqjLhk/" rel="nofollow">https://jsfiddle.net/y9kqjLhk/</a></p>
  
  <p>Any ideas?</p>
  
  <p>Thanks</p>