Currently if React is not loaded, ReactDOM shows this:

<img width="664" alt="screen shot 2017-08-08 at 3 36 52 pm" src="https://user-images.githubusercontent.com/810438/29077217-784c7624-7c4f-11e7-88bc-b055407523a9.png">

We should throw a nicer error message in the entry point I think.
next &&
      next.nodeType !== ELEMENT_NODE &&
      next.nodeType !== TEXT_NODE
    ) {
      next = next.nextSibling;
    }
    return (next: any);
  },
  hydrateInstance(
    instance: Instance,
    type: string,
    props: Props,
    rootContainerInstance: Container,
    internalInstanceHandle: Object,
  ): null | Array<mixed> {
    precacheFiberNode(internalInstanceHandle, instance);
    
    
    updateFiberProps(instance, props);
    return diffHydratedProperties(instance, type, props, rootContainerInstance);
  },
  hydrateTextInstance(
    textInstance: TextInstance,
    text: string,
    internalInstanceHandle: Object,
  ): boolean {
    precacheFiberNode(internalInstanceHandle, textInstance);
    return diffHydratedText(textInstance, text);
  },
  didNotHydrateInstance(