Implement PING to in-room participant

ref #2575

Add utils::revstr

Implement PING, user to user only (XMPP and IRC side, using CTCP PING)

ref #2757

Rename iq_responder_callback_t to irc_… and add the equivalent to wait for iqs

Merge branch 'v1'

[spec] Update the URL, and do not hardcode the version in it

Escape a # in biboumi.1.md

Wrap a paragraph from INSTALL file to 79 chars

Merge branch 'v1'

Conflicts:
	CMakeLists.txt

Update spec file to 1.1

Send a proper error on IRC message 438 (nickname change too fast)

fix #2576

Use generic send_presence_error() instead of almost identical specializations

Run the service with the nobody user

Do not create a useless biboumi unix user with the RPM package

Add two missing type="error" in some presence errors

Release version 1.1

Merge branch 'v1'

Conflicts:
	src/network/socket_handler.hpp

Fix IPv6 support (sockaddr size)

Since struct sockaddr is too small to contain an IPv6, we use struct
sockaddr_in6 instead, and we cast it where needed

Provide WITHOUT_BOTAN and WITHOUT_SYSTEMD cmake flags

Use them to build without linking to them, even if they are on your system

Send the reason of the connection close to the user