2.5.0

[bstaruk]

This is a minor release that focused on cleaning up the boilerplate HTML/CSS/JS, as well as the webpack configs.

• webpack aliases have been removed completely, as they are no longer needed. all paths that are not relative will start from /src. So import 'css/test.css' would resolve to /src/css/test.css. No need for @css anymore.
• cross-env has been added to the project so that we can access process.env reliably in our JS. We're using this to only run OfflinePlugin on production builds, but it could be used for so much more (omitting analytics from dev, etc).
• The boilerplate has been updated to make a simple fetch for repo details, to provide a demo JS component and to give us something to import fetch/promise polyfills for. I've always wanted these to be opt-in instead of opt-out but there was no solid reason to before now.
• All dependencies updated.. naturally!