title: Ng-table select filtering issue
body: <p>I am trying to filter the ng-table data with select drop down, the issue is select dropdown the values are not populating and ofcos filtering doesn't work, i am using ng-table 2.1.0 version. i tried changing the $scope.names object to hardcoded object i.e., <code>$scope.names=[{title:'Moroni'},{title:'Enos'},{title:'Jacob'}];</code> then values are populating in select dropdown i am assuming there must be property 'title' for every object, but still filtering doesn't work either, is there anything missing here? plunker <a href="https://plnkr.co/edit/JXKgQTRMJYyIsgoaeewu?p=preview" rel="nofollow noreferrer"><code>Here</code></a></p>
  
  <p>Any help is much appreciated.</p>