hellabot.go
func (bot *Bot) WaitFor(filter func(*Message) bool) {
	for mes := range bot.Incoming {
		if filter(mes) {
			return
		}
	}
	return
}
func (bot *Bot) WaitFor(filter func(*Message) bool) {
	for mes := range bot.Incoming {
		if filter(mes) {
			return
		}
	}
	return
}
// WaitFor will block until a message matching the given filter is received