* add experimental babel-plugin-macros support

closes #2730

This will remain undocumented until the brave have tried it in the wild.

**Test Plan:**

There's currently no established way to test changes to
`babel-preset-react-app`. But I did create
[`unmaintained-react-scripts-babel-macros`](https://www.npmjs.com/package/unmaintained-react-scripts-babel-macros)
[a while back](https://github.com/facebookincubator/create-react-app/issues/2730#issuecomment-328153982)
and it worked well.

* Pin the version

 - babel-preset-react-app@3.1.1
 - create-react-app@1.5.0
 - eslint-config-react-app@2.1.0
 - react-dev-utils@5.0.0
 - react-error-overlay@4.0.0
 - react-scripts@1.1.0

* Add warning when HOST environment variable is set (#3719)

* Improve HOST environment variable warning message

* Adjust text and message

Closes #3719

* Always include destructuring transform

* Fix lint

* Bump detect-port-alt

* Bump again

* Switch to Yarn Workspaces

* Feedback

* Move flowconfig

* Use publish script

* Keep git status check

* Fix Flow without perf penalty

* Remove Flow from package.json "test"

* Try running it from script directly (?)

* Try magic incantations

* lol flow COME ON

* Try to skip Flow on AppVeyor

* -df

* -df

* -df

* Try to fix CI

* Revert unrelated changes

* Update CONTRIBUTING.md

* add link to deployment docs after build

* Update printHostingInstructions.js

* Use proxy for all request methods other than GET

* Add comment

* Replacing literal 'build' with `buildFolder` variable

* Cleaning up the printHostingInstructions a bit

* Fixing undefined variable

* Extend --scripts-version to include .tar.gz format

* Removal of debug console.log

* added getProxy

getProxy checks proxy settings from process.env.https_proxy or Yarn (NPM) config (.npmrc)

* changed yarn for npm to get https-proxy 

default value for https-proxy is null, not undefined like in yarn

awk splits lines based on spaces, which causes directory names with spaces to end up in other fields. Using a for loop allows us to print from the 9th field onwards instead of just the 9th field.

* fix #2223 - [feature] Implement dotenv-expand to accept variable expansion in dot env files

* add to README TOC

* fix readme

* Update README.md

* add envinfo package, —info flag

* update envinfo to use new duplicates option

Added some more documentation to install the babel-preset-react-app making it more clear on how to get started with this preset outside of create-react-app.

* Allowing for local "file:" prefixed scripts packages

* Fixing test failure

* Open editor to exact column from build error overlay

* Update launch editor validations

* Better documentation for setupTests.js when ejecting

When running `npm run eject` before creating `src/setupTests.js`, the resulting `package.json` file, won't contain any entry for it - and this is correct in my opinion, since otherwise Jest will crash - but it's useful to have it documented and avoid pointless waste of time.

* Added additional note about src/setupTests.js

Added another note about src/setupTests.js and `npm run eject` in Testing Components section

* Update README.md

* Update README.md

'more' and 'simpler' together is incorrect.

If create-react-app project is ejected and webpack configuration is
modified to multi build setup FileSizeReporter would fail.

In those situations `webpackStats` parameter would contain stats array
for each build. This fix will try to access stats and then falls back
to using plaing webpackStats object.

* Update the string that clears the console.

#1914
I've tested it with Windows 10 and 7, node versions from ~5.0.0 up to 7.7.0.
Didn't managed to test it on 8 but it should be fine.

* Update windows string

Add windows specific string for clearing the console.

* add support to set REACT_EDITOR to none

* change README message

* change condition to avoid problems with editor being null

* move condition to avoid extra code