Remove two sneaky log_debug

Replace all include guards by #pragma once

It’s $CURRENT_YEAR

Style fix

Move all constructors at the top of classes

Convert received modes into roles and affiliations

Use isupport informations to know the user modes when joining

Also remove the duplicate send_self_join methods, user only send_user_join

Implement the Bridge class to translate between the two protocols

Add all useful classes as well: Jid, Iid, IrcChannel, IrcUser etc to
properly keep the informations about what we receive from the IRC server.

Only handle the MUC join stanza, and send the list of users in the IRC
channel to the XMPP user, and the IRC channel’s topic, for now.