Added build step for client side

Starting from this release Cloud Commander uses build step for the client side with help of webpack.

What does it mean is front-end can benefit from

• using es2015
• bundling dependencies
• managing dependencies with help of require
• minifying sources before publishing
• increased load speed

Now client it will contain less code, it will be more flexible and work with it will be more convenient

feature

• (package) scripts: rm:legacy -> rm:client, rm:server
• (cloudcmd) NODE_ENV: debug -> development
• (webpack) turn of uglify when NODE_ENV=debug
• (package) nyc v10.1.2
• (package) scripts: 6to5:client: add --progress
• (package) scripts: add heroku-postbuild
• (package) watch:client:debug
• (webpack) put commons to cloudcmd.js
• (client) es2015-ify
• (rest) rm rendy