match-1.3: ethernet src/dst
match-1.3: add ethertype tests
match-1.3: add IPv4 dscp/ecn tests
match-1.3: add ipv4 proto tests
match-1.3: add ipv4 tcp/udp src/dst tests
match-1.3: add ipv4 src/dst tests
match-1.3: add ipv4 icmp type/code tests
match-1.3: add arp operation test
match-1.3: add arp sender/target tests
match-1.3: add in_port test
testutils: add simple_{tcp,udp,icmp}v6_packet()

These are simplified and IPv6-ified versions of the existing functions.

Also added IPv6 packets to the OF 1.3 ethertype tests.
match-1.3: add IPv6 dscp/ecn tests
match-1.3: add IPv6 proto tests
match-1.3: add IPv6 icmp type/code tests
match-1.3: add IPv6 tcp/udp src/dst port tests
match-1.3: add IPv6 src/dst tests