title: orderBy on value in object with ui-typeahead
body: <p>I am trying to orderBy major in the following list of objects with my ui-typeahead input.</p>
  
  <pre><code>[
      {
          name: 'London (LHR)',
          code: 'LHR',
          country: 'GB',
          major: 1
      },
      {
          name: 'Gatwick (LGW)',
          code: 'LGW',
          country: 'GB',
          major: 0
      }
  ]
  
  &lt;input 
      type="text" 
      name="destination" 
      uib-typeahead="airport as airport.name for airport in getAirports($viewValue) | filter:$viewValue | orderBy:airport.major | limitTo:8" 
  /&gt;
  </code></pre>
  
  <p>I tried "major" and "airport.major" as in the above example. Major essentially reflects if an airport is a big one. For example London Heathrow would be a 1, while Gatwick would be a 0.</p>
  
  <p>getAirports() creates my Airports object as the output needs some validation on the airport names. </p>
  
  <p>orderBy has no effect, can anyone spot where I am going wrong?</p>