* Whitelist files that can be embedded through url-loader

Change the current catch-all loader to use file-loader instead of
url-loader, and exclude common image file extensons. Add another url-loader
for images, configured identically to the original catch-all loader.

Part of issue #1293.

* Update tests to reflect change in loader config

* Integration test fix

* More CI fixes

* Work around broken loader-utils behaviour in integration tests

* Revise the documentation around file loading

* Documentation tweaks

* Docs tweak

* Update test now that webpack/loader-utils has been updated

* Update react-scripts to depend on babel-loader@7.0.0-alpha.2

* Bump deps

* Lint internal scripts with eslint:recommended

* Warnings r bad

* Test basic import syntax

* Compile import() in test, only support syntax otherwise

* Disable require.ensure

* Replace require.ensure with import

* Add babel plugin for parsing import()

* Get the default

* Upgrade babel-eslint to support dynamic import

* Fix dep

* Update deps

* Upgrade webpack

* Address more webpack v2 ...

* Update html-webpack-plugin

* Remove LoaderOptionsPlugin from dev config

* ExtractTextPlugin still uses webpack 1 syntax
... and doesn't support complex options (yet)

* Grammar nit

* Update extract text webpack plugin

* - Remove webpack.LoaderOptionsPlugin
- Update deps

* Lerna hoists packages

* Update extract-text-webpack-plugin

* Update webpack-dev-server

* Remove imports for the tests

* stop removing babelrc

* Add `PUBLIC_URL` env variable for advanced use (#937)
* Add support for `PUBLIC_URL` env variable
* Remove unnecessary duplications
* Simplify served path choice logic
* Honor PUBLIC_URL in development
* Add e2e tests

Enables serving static assets from specified host.

- code style

* E2E: run tests when react is ready

* Entangle e2e with callbacks

* Remove unused e2e lines

* Use a more sophisticated template for end-to-end testing.

* Not publish integration tests to npm

* Use "commander" for  cli argv handling

* Handle different scripts version forms and exits without a name given

* Prepare the commands for testing with a template

* Fix dev "template" path

* Add various features to test

* Test various features separately

* Test language features

* Comment unused e2e.sh lines

* Add "development" tests

* Test environment variables

* Test webpack plugins

* Replace kitchensink README

* Switch integration tests from jest to mocha

* Use `fs-extra`

* Use the correct folders

* Do some cleanup

* Print a better message for `--template`

* Test `npm start` with and without https

* Separate fast e2e testing from kitchensink testing

* Hide `--internal-testing-template` (former `--template`) CLI option