* Add file_watcher_port in common_site_config.json

* minor

* Fix build.js

* let to var

* Added use_strict flag

* Add new build system requirements

* Fix array includes

* Fix indexof

* added build.js

* js babelify and concat, css concat working

* less wip

* live reload css working

* css reload on less change working

* added watch_js

* setup file watcher only in dev mode, don't compile variables.less

* Minify js files using babili

- Add --minify flag

* Set minify to false as default

* [minor] Remove redundant code

* Used subprocess instead of os.system

- Also added experimental flag