Added .inRunLoop to Function prototype extensions

This change does what it sounds like:

```javascript
Ember.$.ajax("/url", "GET", {
  success: function(result) {
    obj.set('foo', result);
  }.inRunLoop()
});
```

which is shorthand for 

```javascript
Ember.$.ajax("/url", "GET", {
  success: function(result) {
    Ember.run(function() {
      obj.set('foo', result);
    });
  }
});
```