* Make CoreDNS a server type plugin for Caddy
Remove code we don't need and port all middleware over. Fix all tests
and rework the documentation.
Also make `go generate` build a caddy binary which we then copy into
our directory. This means `go build`-builds remain working as-is.
And new etc instances in each etcd test for better isolation.
Fix more tests and rework test.Server with the newer support Caddy offers.
Fix Makefile to support new mode of operation.
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.
