* Fix the e2e test

In the end-to-end test, we want to test all the latest packages from
the monorepo instead of the versions from npm.

To do this we will now:
* run `lerna bootstrap` in the repo root folder before packaging react-scripts
* bundle the deps like we do for releases, so the e2e test uses those packages

* Fix copy-pasted comment

* Update eslint-plugin-react and enable new rules

New rules:
* `react/no-danger-with-children` (yannickcr/eslint-plugin-react#710)
* `react/no-find-dom-node` (yannickcr/eslint-plugin-react#678)
* `react/style-prop-object` (yannickcr/eslint-plugin-react#715)

* Remove react/no-find-dom-node for now

* Move ESLint configuration to a separate package

* Remove the ESLint configuration, moved to eslint-config-react-app

* Update ESLint instructions

* Pin the package versions in eslint-config-react-app

* Add a README for eslint-config-react-app

* Update README.md

* Update README.md

* Update README.md

* Update README.md

* Update package.json

* Update package.json

* Update production eslint-loader config

* Add the ESLint config to devDependencies of the repo

* Revert "Add ES5 version of `path-exists` to CLI"

This reverts commit fc3ab46d.

* Use pre node@4 compatible `path-exists`

Ref #617

The commit 26464096 moved the documentation files without updating the links in the main README.md

Removed rwb and rackt-cli because they’re not actively maintained and use Babel 5.
Also removed budō because it has a different focus.

* Add 0.4.2 changelog

* Update CHANGELOG.md

Collecting all the relevant details early on means less back and forth
between the poster and project contributors. Asking to create a small
reproducible demo means less time wasted trying to repro the bug.

Brunch has been doing this for a while and it has really helped.
There are people who deleted the template and went free-form in their
bug reports but for the most part, people have actually been filling
that in:
https://github.com/brunch/brunch/issues?q=is%3Aissue+is%3Aclosed

A lesser percentage of the people were creating the demos, but a few
definitely were. The details, and the demos especially, led to faster
resolution times, which a win for everyone.

Fixes #498

* Split no-unused-vars ESLint config to multiple lines

* Exempt variables prefixed with underscore from no-unused-vars rule

This is useful when e.g. using object spread operator to remove only a
certain field from the object.

For example, this can be used to ignore a property from React
component's `this.props`:

    render() {
        const { someAttribute: _unused, ...rest } = this.props;
        return <pre>{ JSON.stringify(rest) }</pre>;
    }