address types for 802.11.
Support the OpenBSD names for some of the 802.11 frame types.
Support OpenBSD's "dir" keyword for 802.11 frame directions.
types. Modified to add ieee80211.h from FreeBSD, rather than depending
on the OS supplying the header, and to support all 802.11 radio header
Clean up some link-layer type checks and the messages for failing those