Template generation

This completes items 1 and 2 on the To Do list in the readme: *Generate objects to store compiled mustaches* and *Generate template traits to make rendering templates easy*.

With this if you have a template sitting at `src/main/mustache/foo.mustache` then a template trait will be generated in `mustache.foo` which you can extend:

`mustache/foo.mustache`:
```
<h1>{{page_title}}</h1>
```

Presenter code:
```
case class Foo(
    page_title:String
    //other model parameters
) extends mustache.foo

Foo(page_title = "Rendered by Mustache").render
```

Rendered output:
```
<h1>Rendered by Mustache</h1>
```

Easy.