chore(pkg): gulp-clean-css 2.2.0 - close #336, babel-core 6.20.0 - close #337
chore(pkg): gulp-clean-css 2.2.0 - close #336, babel-core 6.20.0 - close #337

localnerve/react-pwa-reference,localnerve/react-pwa-reference,localnerve/react-pwa-boilerplate,localnerve/react-pwa-boilerplate