packet-ax25.c and packet-arp.c.
Add an "ax25.pid" dissector table for those protocol IDs, use it in the
AX.25 dissector, and have dissectors register in that table with their
protocol IDs.
Get rid of some unneeded includes.
Clean up some "AX25"s in user-visible strings - say "AX.25" instead.
Clean up some indentation.
svn path=/trunk/; revision=44235
Guy Harris