* Fix file middleware to use a proper zone implementation
    * Zone parsing (better zone impl.)
* Zones file parsing is done twice on startup??
* Cleanup/make middlewares
    * Fix complex rewrite to be useful
    * Healthcheck middleware
    * Slave zone middleware
    * SkyDNS middleware, or call it etcd?
* Fix graceful restart
* TESTS; don't compile, need cleanups
* http.FileSystem is half used, half not used. It's a nice abstraction
    for finding (zone) files, maybe we should just use it.
* prometheus:
    * track the query type
    * track the correct zone

When there is already something running.

BUG: server/server.go ListenAndServe
Activating privacy features...
.:1053
panic: close of closed channel

goroutine 40 [running]:
panic(0x8e5b60, 0xc8201b60b0)
	/home/miek/upstream/go/src/runtime/panic.go:464 +0x3e6
github.com/miekg/daddy/server.(*Server).ListenAndServe.func1.1()
	/home/miek/g/src/github.com/miekg/daddy/server/server.go:147 +0x24
sync.(*Once).Do(0xc82011b830, 0xc8201d3f38)
	/home/miek/upstream/go/src/sync/once.go:44 +0xe4
github.com/miekg/daddy/server.(*Server).ListenAndServe.func1(0xc82011b4c0, 0xc820090800, 0xc82011b830)
	/home/miek/g/src/github.com/miekg/daddy/server/server.go:148 +0x1e3
created by github.com/miekg/daddy/server.(*Server).ListenAndServe
	/home/miek/g/src/github.com/miekg/daddy/server/server.go:150 +0xfe