* 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

* Fix instructions for serving with now

Not sure if new, but the `--single` flag is now important.

* Keep it shorter

* Update README.md

* Update README.md

* Suggest to create .eslintrc for IDE lint plugins

* Update README.md

* Update README.md

* Define dev chunk names

Fixes #2046

* Add comment

* Modularize and extract crashOverlay to iframe

* Do not break words

* Disable warning overlay

* Use CJS imports

* resolves facebookincubator/create-react-app#1986 updates CSS Preprocessor docs to include information on node-sass-chokidar alternative to node-sass

* Update README.md

Minify and map css

* Change proxy localhost to I27.0.0.1 for windows

* Update comment

* resolve localhost IP with DNS lookup on windows

* Fix CI errors

* Promisify addWebpackMiddleware

* Remove Node 6 syntax

* Update addWebpackMiddleware.js

* Actually use the resolved proxy

* removed redundant already default options in UglifyJsPlugin

* re-enabled remove comments Uglify option

JSDoc-style comments weren't being removed

* Node.js serving with absolute path

It’s safer to use the absolute path of the directory that you want to serve, in case you run the express app from another directory.

* Update README.md

Pass the host from environment variable as argument of the devServer's
listen function instead of a field of options object.
Set the default host to 0.0.0.0 instead of localhost.

* Fix npm to yarn

* yarn & npm

* Update index.html

* Switch ordering of suggestion

We should suggest NPM first for new users.

* Upgrade webpack & related deps

* Disable module transform (requires webpack 2+)

* Fix importing npm linked libraries

* Update webpack.config.dev.js

* Update webpack.config.prod.js

Previous changes caused `detect-port` to pick random port on app startup. Update fixes this regression, `detect-port` pick next available port instead.

Resolves #1818

* Adding shrink-to-fit=no for proper responsive handling on Safari 9+

commander to figure it out on its own

* Removed blockquote from code section

* Fix the fix

* Allow creation of apps in empty mercurial repos

* Adding .hgignore to list of validFiles for isSafeToCreateProjectIn check

* Adding .hgcheck to list of validFiles for isSafeToCreateProjectIn check

* Makes end-to-end testing crash on unhandled rejections

* Comment fix

* Fixes a silent crash when ejecting

* Delete unnecessary files

* Remove references to eslintrc in Webpack config

* Fix lint

* Correct ESLint CLI options

* Fix for issue #1798: Suggested 'yarn build' versus 'yarn run build'

* remove 'run' from 'yarn test' command as well

* conditionally show 'run' if Yarn is not available