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.
Cache the size and the do bit whenever someone asked for it. We can
probably add more:
PASS
BenchmarkStateDo-4 100000000 11.9 ns/op
BenchmarkStateSize-4 5000000 265 ns/op
ok github.com/miekg/coredns/middleware 2.828s
PASS
BenchmarkStateDo-4 1000000000 2.86 ns/op
BenchmarkStateSize-4 500000000 3.10 ns/op
ok github.com/miekg/coredns/middleware 5.032s
This PR also includes some testing cleanups as well.
