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

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

Cleanup of netatalk atalk layer includes, protocol definitions, and
routing:

- style(9) cleanup -- white space, braces, etc.

- Make include guards consistent with our more general naming
convention.

- Rearrange and complete forward structure declarations in at_extern.h,
remove testing of guards of various other include files to protect
function declarations.

This leaves an ifdef _KERNEL in at_var.h, but from inspection it seems
likely that this file is not actually safe for inclusion in user space
still. However, since it's not included from within src/ so this does
not appear to be an issue (ifconfig, etc, have migrated to the generic
cross-protocol ioctls for address operations).

/* -> /*- for license, minor formatting changes, insert COPYRIGHT into files

Add more ethernet types and move AppleTalk types into proper location.

Obtained from: NetBSD (syssrc/sys/net/ethertypes.h, rev.1.13)

Fixed pedantic syntax errors.

Staticicized.

Add code to automaticall support subnets on ethertalk networks
Subnets are represented in the routing table as a set of
binary routing nets using the standard netmask algorythm.
The code produces the minimum possible set of standard netmasks and
net addresses to be able to represent a given netrange.

Submitted by: archie@whistle.com

appletalk cleanups

Obtained from: netatalk distribution netatalk@itd.umich.edu

Kernel Appletalk protocol support
both CAP and netatalk can make use of this..
still needs some owrk but it seemd the right tiime to commit it
so other can experiment.