Uses litesql

Each IrcClient callback has a max and min size of argument, we call the
callback only if the parsed message has a correct number of arguments,
otherwise it is ignored (with a warning logged).

Also fix some constness things

Use map instead of unordered map (it's not slower, and it's shorter).
Use the default move constructor.

On my poor benchmark, it was infinitesimally faster.

Remove the close() method and closed attribute. Remove all the calls to
close().  (Save one bool per XmlNode, yay, and save a few ifs and some
useless function calls. At best it should be unnoticeably faster and lighter
and save a few keystrokes in the future)

The server will respond with the current channel mode, in private or
something

fix #3083

ref #3083

This helps the system understand if the process started correctly or not,
when systemd is not used

fix #3078

They were not able to execute them anyway, so this was just a little
usability issue.

This reverts commit 54f96deb.

Because this is a nightmare to manage

They are atomically unblocked in the ppoll/epoll_pwait calls, avoiding any
race condition on the check of the “stop” or “reload” booleans.

Some XMPP client ping themselves inside MUCs, to know if they are still in
there, this created a flood of PING message in private.  If the user is
interested in knowing when they receive a ping or version request, they can
still read their XML logs

fix #2472

ref #2472

ref #2472

Our CTCP notice didn't include a \01 char at the end.  We thus failed to
check the PING id when we received it ourself, because one char was missing

fix #2694

fix #3041