add CVS to usr.sbin (makes future cvs co's easier)
add ndp(8) (more or less ipv6 arp(8) equivalent)
add tcpdump (required by ndp for a silly reason)
Merge branch 'netbsd-cvs'

Conflicts:
	CVS/Entries
	CVS/Entries.Log
	usr.sbin/CVS/Entries
actually merge the cornflakes (due to some gitty gitness on my part)