ip: Protocol Independent IP Neighbors

Type: feature

 - ip-neighbour: generic neighbour handling; APIs, DBs, event handling,
aging
 - arp: ARP protocol implementation
 - ip6-nd; IPv6 neighbor discovery implementation; separate ND,
MLD, RA
 - ip6-link; manage link-local addresses
 - l2-arp-term; events separated from IP neighbours, since they are not
the same.

vnet retains just enough education to perform ND/ARP packet
construction.
arp and ip6-nd to be moved to plugins soon.

Change-Id: I88dedd0006b299344f4c7024a0aa5baa6b9a8bbe
Signed-off-by: Neale Ranns <nranns@cisco.com>

test/test_srmpls.py

@@ -84,7 +84,6 @@ class TestSRMPLS(VppTestCase):
         for i in self.pg_interfaces:
             i.unconfig_ip4()
             i.unconfig_ip6()
-            i.ip6_disable()
             i.disable_mpls()
             i.admin_down()
         super(TestSRMPLS, self).tearDown()