Pull up following revision(s) (requested by roy in ticket #159):
	sys/netinet6/nd6.c: revision 1.153
Tests for neighbour now work correctly on bridge(4) and carp(4) interfaces.
Pull up following revision(s) (requested by roy in ticket #160):
	sbin/ifconfig/af_inet6.c: revision 1.30
	sbin/ifconfig/ifconfig.8: revision 1.109
	sys/netinet6/in6.c: revision 1.177
Remove the ability for userland to toggle IN6_IFF_TENTATIVE.
Preserve IN6_IFF_TENTATIVE when updating address flags.
Tickets #159 and #160