Implemented update_port

**note**: this is broken for deallocated ips (should I add a layer to ipam or can I query/modify the deallocate bit from plugin? do we still need the deallocate bit since we have an ip-port association table, or would that be an extra non-performant lookup?

the algorithm of picking the next ip to allocate is broken by letting the user choose their ip address. will have to figure out a new algorithm to do that... .