Implement part and join, both ways

Remove IRC colors from the body when forwarding it to XMPP

Cosmetic

Check UTF-8 encoding, and convert strings to UTF-8

Handle conversion errors properly by inserting � instead.  Add a binary
header to provide portable way to write binary literals (I like them) Also
add a test file.  ref #2404

Send and receive messages

Also correctly respond to PING with the id, escape some XML content, but not
always

Add make_unique.hpp and split.hpp

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.

Add FindCryptoPP to the cmake search stuf

Exit the poller when it handles no connection at all

Add a basic XMPP component implementation, doing the authentication

Add an XmppParser, and Stanza classes

Generate events on stanza and stream open/close.
Create Stanza and serialize them.

Note: XML namespaces are not handled yet.

Rename libirc and libxmpp to irc and xmpp

Add initial CMakeLists.txt that compiles the current code

Move the basic socket implementation into the SocketHandler class

(that is, the read/write/connect/etc)
Because this code is actually common for both the IrcClient and
XmppComponent class. These two classes have to implement some higher level
callbacks (parsing the data provided in the buffers, doing stuff when the
connection is done) instead of doing the read/write/connect low level
things.

Add irc_message.hpp

Basic IRC message parsing/sending

Add some dummy main

First step of the connection skeleton

Basic connect, socket creating, polling, recving, etc.