arpa: parse received ARP packets
arpa: add a function to send an ARP packet
arpa: reply to ARP requests for the virtual router
arpa: ratelimit packet parse error log
arpa: wrap long lines
arpa: drop packet-in when not addressed to virtual router
arpa: use ARP header source MAC for reply Ethernet dest MAC
arpa: clarify comment on constructing the ARP reply
arpa: remove redundant PPE header check
update loxigen-artifacts

* submodules/loxigen-artifacts a58cae9...df3e83b (10):
  > Artifacts from https://github.com/floodlight/loxigen/compare/f63d027cce0f71a58337cfd17d26f3d50c5ad775...f8498dd3102a8e03596d821c1b1c9ca80e4145d7
  > Artifacts from https://github.com/floodlight/loxigen/compare/1e7c7219a666e15027d720f1a82d4f801dc2d337...f63d027cce0f71a58337cfd17d26f3d50c5ad775
  > Artifacts from https://github.com/floodlight/loxigen/compare/0887d3e1cef714a077fa87c8a605750ebbc0d066...1e7c7219a666e15027d720f1a82d4f801dc2d337
  > Artifacts from https://github.com/floodlight/loxigen/compare/17eaa9ce897e45b94d6c2cbb4a6f287c0ca70c05...0887d3e1cef714a077fa87c8a605750ebbc0d066
  > Artifacts from https://github.com/floodlight/loxigen/compare/6e294db14a7affef0f0061bcc6dcc92d3f101775...17eaa9ce897e45b94d6c2cbb4a6f287c0ca70c05
  > Artifacts from https://github.com/floodlight/loxigen/compare/31cc0668867d1eb9a2fc578bd56e935bad49a95c...6e294db14a7affef0f0061bcc6dcc92d3f101775
  > Artifacts from https://github.com/floodlight/loxigen/compare/1223812e8de24c740b5b7dba139a8c9e818e38c7...31cc0668867d1eb9a2fc578bd56e935bad49a95c
  > Artifacts from https://github.com/floodlight/loxigen/compare/527015eae8a000d79d6369fbe56c0fab59bdf0fa...1223812e8de24c740b5b7dba139a8c9e818e38c7
  > Artifacts from https://github.com/floodlight/loxigen/compare/08e2b473ef6ba64cd94ed40c4812b35cef0dcf93...527015eae8a000d79d6369fbe56c0fab59bdf0fa
  > Artifacts from https://github.com/floodlight/loxigen/compare/6310e32972c597bd460293fd87abccf1fa35d805...08e2b473ef6ba64cd94ed40c4812b35cef0dcf93
Merge into master from pull request #17:
arpa: Reply to ARP requests for the router IP (https://github.com/floodlight/switchlight-common/pull/17)