Summary:
This change (initially discussed in https://github.com/react-community/create-react-native-app/issues/26) moves the HelloWorld project template from two nearly identical entry points (`index.android.js` and `index.ios.js`) to a single, minimal `index.js` entry point. The root component is created in `App.js`. This unifies the project structure between `react-native init` and Create React Native App and allows CRNA's eject to use the entry point from the HelloWorld template without any hacks to customize it. Also examples in the docs can be just copy-pasted to `App.js` the same way in both HelloWorld and CRNA apps without having to first learn about `AppRegistry.registerComponent`.
* Created a new project from the template using `./scripts/test-manual-e2e.sh` and verified that:
* The app builds, starts and runs both on Android and iOS.
* Editing and reloading changes works.
* The new files (`index.js`, `App.js`, `__tests__/App.js`) get created in the project folder.
<img width="559" alt="screen shot 2017-08-01 at 19 10 51" src="https://user-images.githubusercontent.com/497214/28835171-300a12b6-76ed-11e7-81b2-623639c3b8f6.png">
<img width="467" alt="screen shot 2017-08-01 at 19 09 12" src="https://user-images.githubusercontent.com/497214/28835180-33d285e0-76ed-11e7-8d68-2b3bc44bf585.png">
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Closes https://github.com/facebook/react-native/pull/15312
Differential Revision: D5556276
Pulled By: hramos
fbshipit-source-id: 068fdf7e51381c2bc50321522f2be0db47296c5e
6e99e314b2
