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.
This implements stubzones in the same way as SkyDNS. This
also works with multiple configured domains and has tests.
Also add more configuration parameters for TLS and path prefix and
enabling stubzones. Run StubUpdates as a startup command to keep up to
date with the list in etcd.
