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

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

Sync with recent changes from luigi - struct ng_ipfw_tag superceeded
by more general ipfw_rule_ref. The latter isn't documented here, since
it should be documented in ipfw.4.

Sync struct ng_ipfw_tag description with sources.

Submitted by: Mikolaj Golub

English and mdoc(7) cleanup.

Submitted by: ru

Manpage for ng_ipfw node.