Readme seems only to apply to v1.3.0

The User.getNotification method is only avalaible when using

```
<script src="//npmcdn.com/github-api@v1.3.0/dist/GitHub.bundle.min.js"></script>
```

and not with 

```
<script src="//npmcdn.com/github-api@v2.0.0/dist/GitHub.bundle.min.js"></script>
```
