Setup ExpressJS structure

Add required modules
Add Jade view engine
Setup routes
Start converting html to jade
Add layout view
Convert some html to jade views

Convert pad and screen.
Update style
Add save and upload level levels logic
Replace "platform" term with "level"
Add create platform
Add lobby view

The lobby allows to create or choose un level
Add sign in/sign up/sign out
Add edit level
Add delete level
Add rename level
Merge branch 'ui'

Conflicts:
	public/js/screen.js
Clean up
Update README

Add informations about data management