Add "Documentation" variables to systemd configuration files

Merge branch 'systemd' * systemd: ngircd.sock: explicitely bind to IPv4 and IPv6 addresses Show address and port of sockets passed-in by systemd(8) Check type of sockets passed-in by systemd(8) Adjust severity levels of some log messages New configuration option "IdleTimeout": exit daemon when idle Implement support for systemd(8) "socket activation" contrib/README: add more files

ngircd.sock: explicitely bind to IPv4 and IPv6 addresses

Implement support for systemd(8) "socket activation" This patch enables ngIRCd to work with listening sockets already initialized and passed-in by systemd(8) and hereby to support on-demand "socket activation". systemd(8) uses two environment variables to pass information about the sockets to ngIRCd, LISTEN_PID and LISTEN_FDS, and this mechanism only kicks in when both variables are set. In all other cases, and therefore in most installations out there, nothing changes at all. Please note: If socket activation is in effect, ngIRCd will not initialize any (other) soeckets on its own! All sockets must be configured in the systemd(8) socket unit configuration file in this case, see ./contrib/ngircd.socket for example. Probably it would be interesting to match passed-in sockets to configured listening sockets and to initialize all the remaining ones not already set up by systemd(8), but this is kept back for an other patch ... See - <http://0pointer.de/blog/projects/socket-activation.html> - <http://0pointer.de/blog/projects/socket-activation2.html> - <http://www.freedesktop.org/software/systemd/man/systemd.socket.html>