treat channel founder as such even if they don't have +q

This affects /TOPIC, /INVITE, and a few others.

irc/channel.go

 func (channel *Channel) ClientIsAtLeast(client *Client, permission modes.Mode) bool {
 	channel.stateMutex.RLock()
 	clientModes := channel.members[client]
+	founder := channel.registeredFounder
 	channel.stateMutex.RUnlock()
 
+	if founder != "" && founder == client.Account() {
+		return true
+	}
+
 	for _, mode := range modes.ChannelUserModes {
 		if clientModes.HasMode(mode) {
 			return true