changes:
- Update to new webpack build/dev system
- Switch from SCSS to PostCSS
- Add npm scripts for build/dev/lint etc.
- Change CSS linting to stylelint with new config
- Add support for hot updates to scripts and stylesheets without browser refresh
- Replace manually entered eslint config with eslint-config-planetary
- Add support for inlining images under 10kb as base64
- Add support for long term asset caching