* Support webpack 2

* Code style

A previous commit renamed the apple script to open chrome from
`chrome.applescript` to `openChrome.applescript`. That created
a minor bug. Even when chrome was open with the client app,
`npm start` would open the client app in a new Safari tab on
macOS instead of re-using the open tab in chrome.

 - react-dev-utils@0.2.1
 - react-scripts@0.6.1

* Add syntax error overlay in development

* Support HMR being disabled

* Tweak CSS

Fixes https://github.com/facebookincubator/create-react-app/issues/625#issuecomment-249320724.

* Extract some utilities into a separate package

* Add utils dir to `files` in package.json

* Do not create an empty `utils` dir on eject