title: model is not being updated in directive's click event
body: <p>I have following line of code.</p>
  
  <p><strong>HTML</strong></p>
  
  <pre><code>...
  &lt;html ng-app="myApp"&gt;
  ....
  &lt;div ng-controller="myController"&gt;
      &lt;div ng-model="info.myField"&gt;&lt;/div&gt;
      &lt;a href="#" my-update field="info.myField"&gt;Update Me&lt;/a&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p><strong>JS</strong></p>
  
  <pre><code>var app = angular.module("myApp",[]){
  app.controller("myController", ['$scope',function($scope){
      $scope.info = {
          myField = "init value"
      };
  }]);    
  
  app.directive("myUpdate",function() {
      return {
          restrict: "A",
          scope : {
              field:"="
          },
          link: function(scope, elem, attrs){
              scope.field = "Updated in link";    //Line A
  
              elem.bind("click",function() {
                  scope.field = "Updated on click";   //Line B
              });
          }
      };
  });
  </code></pre>
  
  <p>When I run this code, controller's info.myField is updated to "Updated in link" (as done in Directive's Line A). When I click "Update Me" anchor, Directive's Line B is executed but controller's info.myField is not updated. </p>
  
  <p>Why info.myField is not being updated in click event? Am I missing something?</p>