Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Drop <bsd.man.mk> support from <bsd.kmod.mk>.

Not objected to by: -current

Add a 'splitter' node to separate a bidirectional
packet flow into two unidirectional flows.

Part of a suite of nodes developed for packet flow control.
More to follow as I have time to port them to 5.x or
as others do so. The ipfw node will be the hardest..

Submitted by: "Vitaly V. Belekhov" <vitaly@riss-telecom.ru>