Code-Splitting

• Implements code-splitting via react-universal-component
  as well as an example for using it.
• Replaces stage-0 with stage-2 babel-plugin
  due to it being a more advanced and stable spec
• Implements configuration for babel-preset-env to make actual use of the preset
• Removes cssHash from the application, since the extract-css-chunks-webpack-plugin
  is no longer implemented since version 2.0.0 of this template
  • There are plans to switch to mini-css-extract-plugin,
    but since it does not yet support HMR, I am gonna wait on that a little

Thanks to @arkhamRejek for contributing the code-splitting feature
as well as the babel-preset changes!