Nickserv

This branch adds nickserv. It is based on db-services branch.
Instead of "commandpermission-PRIVMSG" it may be better to use the generic "commandpermission" action (it's like the one you used only it applies to all commands and has an additional `command` parameter) to only allow a specific set of commands (PING, PONG, NS, PRIVMSG but only to NickServ, etc. The full list is in the old code, I think--yell at me if it's not).