Implement basic IPv6 support and fix some issues with IPv4 routing.
  * Fix issue in policy manager in subnet index when no policy space
    synced
  * Fix issue with populating ARP flows for routers IPs and add tests
    for same
  * Add port security and routing flows for endpoints with ipv6
    addresses
  * IPv6 router does not yet respond to neighbor discovery messages.

Change-Id: Ie0beaeda24d965540f7501000b33e94d9cf4c7a2
Signed-off-by: Rob Adams <readams@readams.net>