Observer targetActions follow paths

When setting observers with targetActions inside a Route's event hash
the targetAction function was not being properly called.

example:

```js
App.NewRecordRoute = Ember.Route.extend({
  events: {
    submit: function() {
      this.controller.get('content').addObserver('id', this, 'afterCreate');
      this.controller.get('strore').commit();
    },
    afterCreate: function() {
      this.controller.get('content').removeObserver('id', this, 'afterCreate');
    }
  }
});
```

because `this` is the scope of the instance of `NewRecordRoute` the `afterCreate` function is actually under `this.events`. So we should properly write it as:

```js
App.NewRecordRoute = Ember.Route.extend({
  events: {
    submit: function() {
      this.controller.get('content').addObserver('id', this, 'events.afterCreate');
      this.controller.get('strore').commit();
    },
    afterCreate: function() {
      this.controller.get('content').removeObserver('id', this, 'events.afterCreate');
    }
  }
});
```

However currently this doesn't work. This PR will allow the paths to be followed.