Migrate Server module to Python3.5 | Rewrite to benefit from asyncio

[panagiks]

This is a milestone for the next version. We should re-implement the Server module to benefit from asynchronous module asyncio. To do this the serve has to be compatible with Python 3.5.

Along with the Server module, a reimplementation of the RESTful API is also planned, to use aiohttp instead of flask.