Support for primitives as target

This pull request adds support for using a primitive as the target of a binding declaration (non-observed). Keep in mind that the binding can still be dynamic, for example you can still add observed properties as formatter arguments which will recompute the value of the binding as they change.

```html
<p>Formatted date: { '2014-10-08' | date user.dateFormat }</p>
```

Where `user.dateFormat` would be something like `"MMM DD, YYYY"`, then the rendered HTML would be:

```html
<p>Formatted date: Oct 08 2014</p>
```

#388