Make the generated app work if you flowcheck it

Created by: lacker

It would be nice if it were possible to add flow to the default project. I tried a minimal flow setup, adding a blank .flowconfig to the root and // @flow to App.css. Four errors:

For the first two I might be configuring things wrong? The second two seem like flow doesn't know how to handle the non-js imports that webpack is handling for us. I'm not sure what the right way to resolve this.

I was using flow version 0.29.0