The IRCv3.1 specification adds the CAP command, allowing
client/servers to enable/disable certain capabilities. The following
patch adds the CAP command, and the response handler for CAP LS, LIST,
REQ, ACK, NAK and error 410 (ERR_INVALIDCAPCMD) messages.

Thanks,
Vibhav
-- 
Vibhav Pant
vibhavp@gmail.com