title: html2canvas text-shadow bug
body: <p>i have this code <a href="http://jsfiddle.net/nuu7B/2/" rel="nofollow">http://jsfiddle.net/nuu7B/2/</a> </p>
  
  <pre><code>html2canvas($('#preview'), {  
      onrendered: function (canvas) {
          var canvasImg = canvas.toDataURL("image/jpg");
          $('#canvasImg').html('&lt;img src="'+canvasImg+'" alt=""&gt;');
      }
  });
  </code></pre>
  
  <p>and i'm using html2canvas to export image. But as you can see, the text-shadow it's not working as it should.</p>
  
  <pre><code>text-shadow: -2px 0 #000, 0 2px #000, 2px 0 #000, 0 -2px #000;
  </code></pre>
  
  <p>i know canvas support text-shadow but the html2canvas is the problem here..</p>
  
  <p>How can I fix that? 
  thanks</p>