update filter orderBy to work with date

HTML

<script src="http://dev.lancevo.net/ngtable/app/lib/angular/angular.js"></script>
<script>
    function Ctrl($scope) {
        $scope.data = [{
            'name': 'Smith, James',
                'dob': '1/12/70'
        }, {
            'name': 'Anderson, James',
                'dob': '1/6/70'
        }, {
            'name': 'Smith, Bob',
                'dob': '1/11/70'
        }];

        // convert string to Date obj
        for (var i = 0, j = $scope.data.length; i < j; i++) {
            $scope.data[i]['dob'] = new Date($scope.data[i]['dob']);
        }
        console.log($scope);
    }
</script>
<div ng-app="">
    <div ng-controller="Ctrl">
        Predicate : {{predicate}} <br>  
        Descending sort : {{reverse}}
        <table>
            <thead>
                <tr>
                    <th><a href ng-click="predicate='name'; reverse =!reverse">Name</a></th>
                    <th><a href ng-click="predicate='dob'; reverse =!reverse">D.O.B</a></th>
                </tr>
            </thead>
            <tbody>
                <tr ng-repeat="person in data | orderBy: predicate:reverse">
                    <td>{{person.name}}</td>
                    <td>{{person.dob | date:'M/d/yy'}}</td>
                </tr>
            </tbody>
        </table>
    </div>
</div>