* 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

* Test Node 9 on CI

* Oops

* 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

All FB open source projects including this one enforce [our code of conduct](https://code.facebook.com/pages/876921332402685/open-source-code-of-conduct), but I just realized we haven't explicitly linked to it from a Markdown file. So I'm doing just that.

* This is a good default.
Adds approx 4 seconds to install time, but can save some headaches.

* Add no lockfile for add, too

* 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

It's been here long enough.

* This doesn't look needed anymore

* Remove unnecessary rebuilds

* Convert e2e-installs

* Convert kitchensink tests

* Upgrade npm for kitchensink

* Run e2e-simple in a realistic scenario

* Use npx for everything

* oops

* Separate old Node E2E test

* Try this for old node

* Try to use Yarn in more E2E scripts

* Keep using npm pack

* Maybe this will fix Windows?

* Try this

* Use latest npm in e2e tests

* Keep default npm version in "simple" test

* Try to fix CI by using a version that supports Yarn

* add link to deployment docs after build

* Update printHostingInstructions.js

* Lint against files with old license

* Update e2e-simple.sh

* Update e2e-simple.sh

* oh no

* 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

* Added documentation for contributors using windows 10

Hopefully encourages devs on Windows machine to contribute

* corrected the wordings a little

* Port cra.sh development task to javascript

* Port cra.sh development task to javascript

Use absolute path when generating .tgz path

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

* Removal of debug console.log