Cleanup docs and the chaos middleware

Make the CH middleware actually work. Needs a bit of a hack to route

the fake version.bind and friends zone to the correct handler. Fiddle

with the order in directive.go so that CH queries get logged as well.



Secondly add class rewriting to the rewrite middleware handler and also

log the class by default.

middleware/chaos/chaos.go

@@ -22,7 +22,10 @@ func (c Chaos) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (
 	if state.QClass() != dns.ClassCHAOS || state.QType() != dns.TypeTXT {
 		return c.Next.ServeDNS(ctx, w, r)
 	}
+
 	m := new(dns.Msg)
+	m.SetReply(r)
+
 	hdr := dns.RR_Header{Name: state.QName(), Rrtype: dns.TypeTXT, Class: dns.ClassCHAOS, Ttl: 0}
 	switch state.Name() {
 	default: