Adding propagation.py, not functionnal yet

Conflicts:
	main.py

    The connections who had failed are now removed correctly from connection_dict

This information is passed to the application

    server and client log file are now opened in WRONLY mode instead of RDONLY
    connections are not refreshed evrytime that a message is transmited on the pipe
Open vpn now trigger client-disconnect
When a new client arrive, its IP is sent to the pipe

Conflicts:
	main.py

Conflicts:
	main.py

Vifibnet now establish a few random connection from a list a given peers and change some evry 2 minutes