Prepare for React 15 upgrade
Prepare for React 15 upgrade

Why:

* The main host app for this module has been upgraded to React 15
* This upgrade revealed conflicts and unnecessary things being added to
the final package

This change addressed the need by:

* Removing `babel/register` import
* Removing `react/addons` from the final bundle

subvisual/react-styleguide-generator,subvisual/react-styleguide-generator