Example not working correctly (any more)

The example is not running correctly any more.

1) package.json

```
"example": "yarn build && cd example && webpack-dev-server",
```

should become:

```
"example": "yarn build && cd example && webpack serve",
```

2) App.js

Controls are not shown. The following import is missing:

```
import 'mapbox-gl/dist/mapbox-gl.css';
```
