title: Content function called twice in Bootstrap Popover
body: <p>I have a Bootstrap Popover which loads a function, like this:</p>
  
  <pre><code>var index = 0;
  
  $('#Button').popover({
      html:true,
      placement:'right',
      content:function(){
        index = index +1;
        return index;
      }
  });
  </code></pre>
  
  <p>And the HTML is just:</p>
  
  <pre><code>&lt;input id="Button" value='popover' type='button'/&gt;
  </code></pre>
  
  <p>So, when I click in the button I should get 1, 2, 3, etc...</p>
  
  <p>However, I'm getting 2,4,6... because it's calling the "content" function twice. Why is that? Is this a bug or am I doing something wrong?</p>
  
  <p><a href="http://jsfiddle.net/d55t7hfa/11/" rel="nofollow noreferrer">Here is the fiddle</a>.</p>