This reverts commit 1dcb3db3.

* Changes no-unused-expressions lint from warning to error

* Update index.js

* Update index.js

* Add restricted globals package

* Use new package in eslint-config

* Add eslint-restricted-globals dependency

* Fixes

* Update dependencies

* Update test and README

* Use jest

* tweaks

* Add lint/test to CI

* Fix lint

* Updating ESlint to ^4.15.0 and adding new rules to config

* remoning style rule and auto fixing breakages from new rules

* Removing implicit-arrow-linebreak style rule

* adding new rule to eslint config project

* updating react scripts eslint version

* Pinning version.

* Changing getter-return to warn

* Update package.json

* Update .eslintrc

* Bump eslint-plugin-jsx-a11y

* Update index.js

* Update index.js

* Update package.json

* Don't use links for non-linky things

Fixes #2793

* File headers BSD+Patents -> MIT

* BSD+Patents -> MIT

* Re-enable flowtype warning

* Update eslint-plugin-flowtype dependency

Until this issue (https://github.com/gajus/eslint-plugin-flowtype/issues/165) is
fixed we're disabling `flowtype/require-valid-file-annotation`.

* Add documentation about using code splitting

* Revise docs a bit

* Update README.md

* Update README.md

* Update README.md

* Bump dependencies

* Bump CSS deps

* Somehow I missed dotenv

* Bump ESLint deps

* Tweak ESLint rules

Removing a stylistic lint rule

* ESLint Config: Upgrade eslint-plugin-jsx-a11y and activate more rules.

* Try to fix Lerna

* Update README.md

* Remove html-has-lang

* Update README.md

* Blacklist confusing global variables

* Blacklist globals

* Fix kitchensink test to lint

* Edit the list

* Use no-restricted globals for this

* Revert "Ignore the yarn cache directory (#2063)"

This reverts commit 94149c77.

* Revert "Forbid using window properties as global variables (#1840)"

This reverts commit 5a7d8e89.

* Forbid using window properties as global variables

* Change globals list to match Standard.

* Fix globals

Iterating over an object's keys using `for/in` is idiomatic and it's safe (in all modern browsers) to not check hasOwnProperty as long as the object is a plain object. Can we remove this lint rule?

* mv create-react-app/index.js -> create-react-app/creteReactApp.js

* update to modern code style

* var -> cosnt

* set trailing-coma to es5 for prettier

* Lint internal scripts with eslint:recommended

* Warnings r bad

* updating eslint to 3.16.1

* add support for ignoreRestSiblings in eslint

http://eslint.org/docs/rules/no-unused-vars#ignorerestsiblings

* updating eslint to 3.16.1 in `react-scripts`

* updating eslint

* missing `^`

* missing ^

* pinning main eslint and updating readme

* Pin ESLint version

* Disallow event global variable with no-restricted-globals rule (#1530)

* changed event global variable usage liniting from warn to error

Revert webpack prod config comments to not refer to dev server.

Enable no-webpack-loader-syntax rule in eslint-config-react-app.