title: iCheck plugin - ifToggled cancel event
body: <p>Is it possible to cancel action of iCheck on ifToggled?
  I have unchecked input:</p>
  
  <pre><code>$('input').iCheck().on('ifToggled', function(e) {
      if (confirm('Don\'t check?')) {
          return false;
      }
  });
  </code></pre>
  
  <p>Input still gets checked (<a href="http://jsfiddle.net/xn60t2c6/" rel="noreferrer">JSFiddle simple example</a>). Is there any way to cancel event?</p>