[WIP] V3 Next version IN PROGRESS

[ryuran]

V3 Work in progress

⚠️ DO NOT MERGE ⚠️

• transform gsk to a node_modules usable as dependency of a project
• add script to initialize a project with gsk
• install dependencies related to config (html and css builder) in init script.
• transform engine html and css to node package to keep init dependencies easier
• rewrite documentation “How to install and use”
• add test with travis
• support node 6.4 to stable
• translate doc to english