make Listen parameter a comma-seperated list of addresses.

make Listen parameter a comma-seperated list of addresses.

this also obsoletes ListenIPv4 and ListenIPv6 options.
If Listen is unset, it is treated as Listen="::,0.0.0.0".

Note: ListenIPv4 and ListenIPv6 options are still recognized,
but ngircd will print a warning if they are used in the config file.

Also, some plattforms require that ai_socktype
is set in the getaddrinfo() hints structure.