Allows nested replacement patterns in string/interpolate

What do you think about allowing nester patterns in the `mout/string/interpolate` module. Pretty much just use `mout/object/get` instead of `replacemtnts[prop]`.

I  find it handy do define objects as such:

```js
{
    name: {
        first: "Mathias",
        last: "Paumgarten"
    }
}
```
and the template like this
```html
<ul>
    <li>{{name.first}}</li>
    <li>{{name.last}}</li>
</ul>
```

This allows you to structure you objects and/or json inputs a bit more.