This is recommended after webpack/webpack#4704

- refactor: Migrate extracted module to lib
- refactor: Migrate order undefined to lib
- refactor: Extract etwp helper functions
- refactor: Extract compilation to stand alone class
- refactor: Proxy plugin module from cjs.js

- refactor: Modernize loader syntax
  - Convert to ES6+ Class
  - Convert to ES6+ default export
  - Convert to const / let
  - Uses import syntax
  - Convert errors to templates

- refactor: Convert tests & configs to import syntax
- refactor: Use indexOf in helpers

- refactor: Modernize plugin syntax
  - Convert to ES6+ Class
  - Convert to ES6+ default export
  - Convert to const / let
  - Uses import syntax
  - Convert errors to templates

- refactor: Modernize ExtractedModule syntax
  - Convert to ES6+ Class
  - Convert to ES6+ default export
  - Convert to const / let
  - Uses import syntax
  - Convert errors to templates

- refactor: Removes fallbackLoader & loader deprecation warnings

- refactor: Removes single option deprecation warning

- refactor: Removes options.loader & options.fallbackLoader

 BREAKING CHANGE: Enforces `peerDependencies` of `"webpack": ">= 3.0.0-rc.0 || ^3.0.0"`.

 BREAKING CHANGE: Enforces `engines` of `"node": ">=4.3.0 < 5.0.0 || >= 5.10`

 BREAKING CHANGE: Updates to `Chunk.mapModules`. This release is not backwards compatible with `Webpack 2.x` due to breaking changes in webpack/webpack#4764

- refactor: Replace usage of chunk.modules with forEachModule, mapModules ect..

  BREAKING CHANGE: Updates to `Chunk.mapModules | forEachModule | getNumberOfModules`. This release is not backwards compatible with `Webpack 2.x` due to breaking changes in webpack/webpack#4764