There’s a common tool included in Hadoop that also has a `yarn` command,
which created issues for users who had Hadoop installed:
* #1257
* #1363

Yarn also installs the command under `yarnpkg` alias (added in
https://github.com/yarnpkg/yarn/commit/cefa9a368dd3df1a1f1ecd9e50de9c5fabefbc92)
so we can use `yarnpkg` instead of `yarn` to make it more reliable.

This has no effect on users who don't have Hadoop installed, but those
who have won't see errors from falsely detecting Hadoop Yarn as Yarn
the package manager, and they can now also install Yarn to make use of
our Yarn support without the Hadoop Yarn interfering.

There’s a common tool included in Hadoop that also has a `yarn` command,
which created issues for users who had Hadoop installed:
* #1257
* #1363

Yarn also installs the command under `yarnpkg` alias (added in
https://github.com/yarnpkg/yarn/commit/cefa9a368dd3df1a1f1ecd9e50de9c5fabefbc92)
so we can use `yarnpkg` instead of `yarn` to make it more reliable.

This has no effect on users who don't have Hadoop installed, but those
who have won't see errors from falsely detecting Hadoop Yarn as Yarn
the package manager, and they can now also install Yarn to make use of
our Yarn support without the Hadoop Yarn interfering.

In the `create-react-app` command, try to install packages using Yarn.
If Yarn is not installed, use npm instead.

In `react-scripts`, detect if the project is using Yarn by checking if
a `yarn.lock` file exists. If the project is using Yarn, display all
the instructions with Yarn commands and use Yarn to install packages
in `init` and `eject` scripts.

Otherwise it makes it an invalid path :(

* Forked react-scripts should retain the binary name

* Forked react-scripts should retain the binary name -- fixed issue with regex

* Forked react-scripts should retain the binary name -- fixed style nit

* Don't hardcode react-scripts package name

Fixes issue described in https://github.com/facebookincubator/create-react-app/issues/682#issuecomment-248781486.

* Update eject.js

Change "configs" to "configuration files" .

* Improve the output of scripts/init.js

* Add semi-colons;

Fixes #532

* Update Jest

* Remove default snapshot test

* Fix a few things

* Add a simple default test

* App.spec.js -> App.test.js

* Fix e2e test

* Bump Jest

* Get latest version numbers of react and react-dom from npm before install.

* Run separate npm installs for react, react-dom, and react-test-renderer.

* Consolidate into a single npm install.

* Fix misplaced parenthesis, add missing semicolon.

* Add missing semicolon.

* Creating a new app in the current directory

* Fixed style mistakes

* Provide instructions on GH Pages deploy

* Add docs for GH Pages deployment

* Prevent incorrect paths in file-loader

* Minor message tweaks

* Update README.md

* Fix relative paths

* explicitly specify ESLint config path for editor plugins

* changed to use single quote

* Adds .gitignore file to default template

* Simplify renames

* Reference npm issue in comment

* Removing leading slash

* Recursively copy the template folder

* add fs-extra library

It is easier to add more scripts later this way.

* Add README to generated project

* add logo.svg

* syntax cleanup