Add model.js script generation

@raymondfeng @bajtos please review
IIRC remoting setup must be wrapped in `Model.setup` function, since the remoting metadata is not inherited when a model is extended.

```js
<%= modelClassName %>.setup = function() {
  <%= modelClassName %>.base.setup.apply(this, arguments);
  this.remoteMethod('myCustomMethod', {
    // ...
  });
}
```