title: setText() not working in fabricjs version 2
body: <p>I am trying to set text to textbox explicitly,in older fabricjs version<code>object.setText("something")</code></p>
  
  <p>was working but not working in fabric js version 2. Any other way introduced in this version?</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>var canvas = new fabric.Canvas('c');
  var text1 = new fabric.Textbox('Text', {
    left: 10,
    top: 20,
     width: 300
  })
  
  canvas.add(text1);
  canvas.on('text:changed', function(e) {
  
   var objTEmp = e.target;
   objTEmp.setText("some");
  
      
  });</code></pre>
  <pre class="snippet-code-css lang-css prettyprint-override"><code>canvas{
   border:1px solid #000;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script type="text/javascript" src="
  https://cdnjs.cloudflare.com/ajax/libs/fabric.js/2.0.0-rc.4/fabric.js"&gt;&lt;/script&gt;
  &lt;canvas id="c" width="400" height="400" style="border:1px solid #000000;"&gt;&lt;/canvas&gt;</code></pre>
  </div>
  </div>
  </p>