Add other STATS subcommands

[ldilley]

The following STATS subcommands are now in place: c (command statistics), d (data transferred), i (admins/opers online with idle time), k (show k-lines), l (list client connections), o (show configured admins/opers), p (show listen ports), q (show q-lines), u (show server uptime), z (show z-lines)

The following STATS subcommands still need to be added: g (show g-lines), m (show memory usage), s (show server links)

[ldilley]

'g' and 's' will be implemented when server linking functionality is added. 'm' may either be removed or show data from the MEMORY STATS command.