Retire struct sockaddr_inarp.

Since ARP and routing are separated, "proxy only" entries
don't have any meaning, thus we don't need additional field
in sockaddr to pass SIN_PROXY flag.

New kernel is binary compatible with old tools, since sizes
of sockaddr_inarp and sockaddr_in match, and sa_family are
filled with same value.

The structure declaration is left for compatibility with
third party software, but in tree code no longer use it.

Reviewed by:	ru, andre, net@
- Move AUTHORS and ACKNOWLEDGEMENTS to the end of the page.
- Add myself to list of authors.
Initial version of libusbboot, a fully stand-alone, single threaded and
functional compilation of the FreeBSD USB stack for use with boot loaders
and such.

Discussed with:		Hiroki Sato, hrs @ EuroBSDCon
Format CDB output as 2 digit hex correcting the length

Approved by:	pjd (mentor)
MFC after:	1 week