Refactor ntpd integration

[fhunleth]

• ntpd now reports status via a Unix Domain socket. This removes the regular expressions and all of the other stuff to try to parse ntpd informational prints.
• Use MuonTrap.Daemon to run ntpd. This removes the raw port handling that looked like it had subtle bugs.
• Detect unclean restarts and delay ntpd from starting. This is an attempt to be a better Internet citizen and prevent ntp servers from being pegged with traffic.
• Add more tests on the NTP daemon code