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

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

/* -> /*- for license, minor formatting changes

Use a single style of multiple inclusion protection for Netgraph headers.

Reviewed by: archie, harti, emax

Finally get around to committing Bill Paul's FEC netgraph nodes.
These are really only partly netgraph nodes as they do not use the
netgraph interfaces for many of the functions for which they could
be used, however they represent important functionality.

Submitted by: wpaul
MFC after: 2 days