Crash when you change your nick

to reproduce :    

     irccon := irc.IRC("gotest", "gotest")
	irccon.VerboseCallbackHandler = true
	irccon.Connect("irc.freenode.net:6667")
	irccon.AddCallback("001", func(e *irc.Event) { irccon.Join("#gotest") })

	irccon.AddCallback("366", func(e *irc.Event) {
		irccon.Privmsg("#gotest", "hi\n")
		irccon.SendRaw("NICK crashmeplz")
	})
	irccon.Loop()