People are using it in prod and some other updates.

Emphasize `go get` as the main way to get the project.

* integration ci

* rename test

* unfunctionalize DoIntegrationTests

* alphabetize expected answers

* Enable out-of-cluster test

* Enable out-of-cluster test

* move integration tests back to ci repo

Some cleanup in proxy and dnstap:
* just use time pkg directly and side step the indirection for Epoch
* Use Set in SetQueryEpoch to be more Go like. (Looked like a reader)
* Don't maintain two sets of time, we already track start, so use that.
* Use time.Time and convert when needed
* dedent the toDnstap function and put in a separate file

If we don't need it, don't initialize it.

Fixes #1156

* core: allow all CIDR ranges in zone specifications

Allow (e.g.) a v4 reverse on a /17. If a zone is specified in such a
way a FilterFunc is set in the config. This filter is checked against
incoming queries.

For all other queries this adds a 'x != nil' check which will not impact
performace too much. Benchmark function is added as well to check for
this as wel.

Add multiple tests in tests/server_reverse_test.go.

Benchmark shows in the non-reverse case this hardly impact the speed:

~~~
classless:
pkg: github.com/coredns/coredns/core/dnsserver
BenchmarkCoreServeDNS-4   	 1000000	      1431 ns/op	      16 B/op	       1 allocs/op

pkg: github.com/coredns/coredns/core/dnsserver
BenchmarkCoreServeDNS-4   	 1000000	      1429 ns/op	      16 B/op	       1 allocs/op

master:
pkg: github.com/coredns/coredns/core/dnsserver
BenchmarkCoreServeDNS-4   	 1000000	      1412 ns/op	      16 B/op	       1 allocs/op

pkg: github.com/coredns/coredns/core/dnsserver
BenchmarkCoreServeDNS-4   	 1000000	      1429 ns/op	      16 B/op	       1 allocs/op
~~~

* README.md updates

This flakyness is driving me crazy. Add the sleep(3s) back.

* stalebot: use wontfix-stalebot

I've added two new labels: wontfix-stalebot and pinned.

Wontfix-stalebot will be used by stalebot and pinned can be used to keep
issues open.

* later as well

Make the locking slightly smarter in Evict and add benchmark function.

Seems a bit faster (there was some variance while performing these
benchmarks)

Master:
BenchmarkCache-2   	 1000000	      2317 ns/op	       0 B/op	       0 allocs/op
BenchmarkCache-2   	 1000000	      2032 ns/op	       0 B/op	       0 allocs/op

This branch:
BenchmarkCache-2   	 1000000	      1806 ns/op	       0 B/op	       0 allocs/op
BenchmarkCache-2   	 1000000	      1809 ns/op	       0 B/op	       0 allocs/op

These file still had middleware in their name, rename to plugin.

* core: add ServeDNS benchmark

Add benchmark function so we can perf test future additions to the
servers' ServeDNS function.

* naming

* plugin/kubernetes: wait until api is ready

Wait for HasSynced before allowing startup to avoid startup race.

Also do a small refactor in findServices() to pull a check out of the
loop - only needs to be done once.

* sigh

Various other changes.

* plugin/dnssec; insert and sign DS records

Sign a delegation as well and insert DS records.

Fixes #698

* better

We support ENV variables in config files, add an example in the one for
metric, note that `localhost:` is a valid host (in Go), so the
TestReadme will parse this correctly.

Fixes #1150

* indexing

* corrections

* Don't number the plugins

The number is not needed, because the ordering is already specified.
It's also annoying when you move plugins, because you need to renumber
them. Remove this.

'go gen' shows no changes in the generated files, meaning this just
works.

* better naming

* plugin/autopath: Add namespace selector and metrics

Add a namespace, so autopathing only is performed in this namespace.
This will make caching work for the cluster again.

Also export metrics that we've done a successful autopath

* dont shadow

* Fix

* Back the namespacing changes

* healthchecks: check on every 3rd failure

Check on every third failure and some cleanups to make this possible. A
failed healthcheck will never increase Fails, a successfull healthceck
will reset Fails to 0. This is a chance this counter now drops below 0,
making the upstream super? healthy.

This removes the okUntil smartness and condences everything back to 1
metrics: Fails; so it's simpler in that regard.

Timout errors are *not* attributed to the local upstream, and don't get
counted into the Fails anymore. Meaning the 'dig any isc.org' won't kill
your upstream.

Added extra test the see if the Fails counter gets reset after 3 failed
connection.

There is still a disconnect beween HTTP healthceck working the proxy (or
lookup) not being able to connect to the upstream.

* Fix tests

Small optimization.

Flaky test because it used a fix port; just drop it. Might be worthwhile
to return it as a unit tests, but on that level we can't use a coredns
"process" to exercise the reload.

See https://github.com/kubernetes/kubernetes/pull/53604, explicitaly add
test to make sure we do the right thing.

* doc update

Go through all README and fix mistakes, extend example and let more
corefile snippets be test for validity.

* Cant use spefic addr in test

Add Counter metrics and fix duration to use upstream name (and only use
it when we have one).

Fix the documentation to reflect this.

Fixes #1134

* add NSEC-records if entry exists but the requested type is missing

* added test for dnssec fix

Clean out the imports in coredns.go and just leave the server import.

Fixes #1119

Use team@coredns.io for reporting sec. vulnerablities. Currenttly this
has john@coredns.io and miek@coredns.io

Make it work with root zone in the query.

close stale issues and stop the merging of PR with WIP in the name.

Fix file/fuzz.go build and docs in Makefile.fuzz
Each plugin can add a fuzz.go to join the fuzzing craze.
pkg/fuzz/do.go could be made a lot smarter, but is probably good enough
for starters.

$ make -f Makefile.fuzz <plugin>

will build with go-fuzz-build and then execute a go-fuzz run. Each
plugin's fuzz run uses a per-plugin directory to store the fuzz data.

We can still be on the receiving end of invalid packet. Drop them
here.

Enable dnstap plugin to insert other plugin's specific data into extra field of tap.Dnstap message (#1101)

* Add custom data into dnstap context

* Fix error and fix UT compile errors

* Add UTs

* Change as per review comments.  Use boolean to indicate which Dnstap message to send out

* Merge with master and fix lint warning

* Remove newline

* Fix review comments