* Fixes front-end dependencies for Amber Framework

- Add node_modules and package.lock to .gitignore
- Add let keyword on amber.js applying #361
- Generate amber.min.js
- Add babel-loader and env preset to webpack config

* Change description

* Add instructions to buid amber.min.js


Former-commit-id: 88327c684ecb10655f160afeef2c68dd8590fdc7