Make middleware that sets up a (http) handler survive a graceful
restart. We calls the middleware's Shutdown function(s). If restart
fails the Start function is called again.
* middleware/health: OK
* middleware/pprof: OK
* middleware/metrics: OK
All restart OK.
Fix CoreDNS graceful reloading. This uses the same stuff as Caddy
(obviously), but extends it for UDP listeners as well. Also add to the
README that we *will* call Shutdown for middleware.
Fixes#4
* Changed reference to Caddy over to CoreDNS
* Removing references to caddy
* Fixed misleading error message to reference coredns
* Cleaning up references to caddy
* Adding clean and deps targets
Muscle memory is resulting in "make clean" commands.
* Adding test target to makefile
* More "Caddy" cleanup
