title: AngularJS: orderBy - string & array are not the same
body: <p>I have an array of users:</p>
  
  <pre><code>$scope.users = [
    {name: 'Anh', age: 10},
    {name: 'Ánh', age: 10},
    {name: 'Ba' , age: 10}
  ]
  </code></pre>
  
  <p>When i use <code>orderBy:'name'</code> the result is:</p>
  
  <ol>
  <li>Anh</li>
  <li>Ánh</li>
  <li>Ba</li>
  </ol>
  
  <p>but when i use multiple fields <code>orderBy:['name','age']</code> the result is different:</p>
  
  <ol>
  <li>Anh</li>
  <li>Ba</li>
  <li>Ánh</li>
  </ol>
  
  <p>Waiting for your help!</p>