daemonized and made related improvements;   - log on syslog   - watch the routing table and reactivate when the default route changed   - reactivate by SIGHUP   - corrected algorithm of resending dhcp6 adverts
daemonized and made related improvements;
  - log on syslog
  - watch the routing table and reactivate when the default route changed
  - reactivate by SIGHUP
  - corrected algorithm of resending dhcp6 adverts

MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame,MarginC/kame