Log Message:
NSD 4.0.0

Features:
* documented in doc/NSD-4-features. Change configuration without restart,
  direct nameserver control with nsd-control, support a higher number of zones.
  Higher performance (compared to NSD3).
* nsdc is gone. Use kill -HUP for reload (also checks if zonefiles have
  changed and rereads them), and kill -TERM for quit. Or use nsd-control
  for detailed control.
* cron job for nsdc patch is gone. nsd-control write creates zonefiles.
* nsd.db has a new format that compacts itself when it is changed,
  thus nsdc patch is no longer necessary.
* nsd.db is memory mapped, NSD needs (part of) that mmap in ram.
* tcp-count can go above 1000; epoll/kqueue support with libevent.
* nsd-control reconfig for updates with no restart (zones, keys, ..)
* nsd-control-setup to create keys for nsd-control (enable nsd-control
  with remote-control: yes in nsd.conf).