See CMP0037

For now, it tries two TLS ports and then connects to the non-tls port.  In
the future we would like the user to be able to configure that.

fix #2435

Also we cannot use both this feature and valgrind at the same time.
So, I’ll just specify this flag myself when I need it, this doesn’t
need to be there by default

Use ccmake, or cmake -i, or cmake -DPOLLER=EPOLL, for example

And now we handle namespaces, yay.
And a nice little test.

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

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.

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

Note: XML namespaces are not handled yet.