Fix nick collision detection.
Fix the crash that happens when WHOing a nonexistent channel.
Update the README.
Add the numeric code for ERR_ALREADYREGISTRED [sic].
Add the numeric code for ERR_CANNOTSENDTOCHAN.
Remove erroneous reference to &-prefixed channels.
Users should not be able to PRIVMSG channels they haven't joined.
Support ERR_NOSUCHNICK and ERR_NOSUCHCHANNEL messages.
Display ERR_NEEDMOREPARAMS errors.
Rename some variables.