Server: Be compatible with WSGI

[staverne]

We want to remove libsoup dependencies and be compatible with WSGI.
We would like to use a server as gevent:

http://www.gevent.org/gevent.html

[jdavid]

I may suggest: (1) upgrade to Python3.5 (2) use async

[staverne]

Thank's for suggestion. It was one of our option...
We should take the time to migrate all our projects to python 3.5
Linked to #67