Merge r27953 from nmap-npingchanges: Add support for ARP Request/Reply packet matching
Merge r27995 from nmap-npingchanges: Add two missing codes. Also, re-write description so it says the same thing as Wireshark.
Merge r27956 from nmap-npingchanges: Improve code description.
Merge r27958 from nmap-npingchanges: Simplify print() in RawData::