Make controllers handle events defined on their prototypes

The following very simple use of `action` doesn't work:

    <script type="text/x-handlebars" data-template-name="application">
    <div {{action "myAction"}}>Action</div>    
    </script>​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

```javascript
App = Ember.Application.create();

App.ApplicationController = Ember.Controller.extend({
    myAction: function(){ alert("it worked")}
});
```

(Runnable version here: http://jsfiddle.net/AMLf4/)

The event fails to fire because `ControllerMixin.send` uses `hasOwnProperty` to determine if the controller can handle the event. In this case (and most cases), the property is defined higher up the prototype chain.