Allow stateless view component

I tried to run the example in `README.md` but i got:

```
warning.js:45 Warning: view(...): No `render` method found on the returned component instance: you may have forgotten to define `render`, returned null/false from a stateless component, or tried to render an element whose type is a function that isn't a React component.warning @ warning.js:45ReactCompositeComponentMixin.mountComponent @ ReactCompositeComponent.js:166ReactCompositeComponent_mountComponent @ ReactPerf.js:66ReactReconciler.mountComponent @ ReactReconciler.js:37ReactCompositeComponentMixin.mountComponent @ ReactCompositeComponent.js:225ReactCompositeComponent_mountComponent @ ReactPerf.js:66ReactReconciler.mountComponent @ ReactReconciler.js:37ReactCompositeComponentMixin.mountComponent @ ReactCompositeComponent.js:225ReactCompositeComponent_mountComponent @ ReactPerf.js:66ReactReconciler.mountComponent @ ReactReconciler.js:37mountComponentIntoNode @ ReactMount.js:266Mixin.perform @ Transaction.js:136batchedMountComponentIntoNode @ ReactMount.js:282Mixin.perform @ Transaction.js:136ReactDefaultBatchingStrategy.batchedUpdates @ ReactDefaultBatchingStrategy.js:62batchedUpdates @ ReactUpdates.js:94ReactMount._renderNewRootComponent @ ReactMount.js:476ReactMount__renderNewRootComponent @ ReactPerf.js:66ReactMount._renderSubtreeIntoContainer @ ReactMount.js:550ReactMount.render @ ReactMount.js:570React_render @ ReactPerf.js:66(anonymous function) @ app.js:92(anonymous function) @ app.js:94(anonymous function) @ app.js:95(anonymous function) @ bundle.js:1007__webpack_require__ @ bundle.js:521fn @ bundle.js:76(anonymous function) @ multi_main:3(anonymous function) @ bundle.js:551__webpack_require__ @ bundle.js:521(anonymous function) @ bundle.js:544(anonymous function) @ bundle.js:547
ReactCompositeComponent.js:587 Uncaught TypeError: inst.render is not a function
```

so replaced the stateless component with:

```
class view extends React.Component {
render(){
const { model, dispatch } = this.props
return (

and it worked.

Reproduce the failure using the README example and the `app.js` entrypoint referenced in the trace so you can confirm the render-path error. Then inspect the library’s view/component mounting code path where it calls `render()` on the mounted instance, and adjust it to accept stateless function components. Run the same example flow again and confirm that the warning and `inst.render is not a function` TypeError do not appear when a stateless `view` is used.

Vom Indexierungsmodell aus dem Issue-Text verfasst.