Created by: gaearon
Addresses https://github.com/facebookincubator/create-react-app/pull/1755#issuecomment-285179758. Since I removed the duplicate filtering hack, this came up again.
Now I'm just showing the first compilation error.
This makes sense because in most cases it's the one you want to fix first anyway. And showing a list is not useful if it's repopulated on every change as you can't easily keep track of it.