Impossible to init a widget from a controller when it's exposed to the parent scope

[tkrugg]

Currently, when a widget is exposed to the parent scope, it is not possible to initialise it from the controller.

<div ng-controller="MainCtrl">
   <ng-star-rating data-id="rate"></div><!-- widget is exposed to $scope -->
</div>

function MainCtrl($scope) {
    $scope.rate.value = 3;        // this will fail because $scope.rate is undefined
    $scope.setRate = function(v){
         $scope.rate.value = v;  // this will work as it's executed after the directive is initialized
    }
}