Allow <script type="application/x-noder" src="foo.js">

Right now we can do

```
<script type="application/x-noder">
  // code here
</script>
```

but can't

```
 <script type="application/x-noder" src="foo.js"></script>
```

As much as trivial it is (and taking into account that usually the scripts we write to start the app will be super small), perhaps it would make sense to add the latter option to satisfy the purists.
