multiaddress filtering
Filtering fixes improvements:

(1) Sometimes we print duplicates when querying our own addresses (`swapcli addresses`). Not sure what specific network setups cause this. We should remove duplicates.
(2) When querying our own address (`swapcli addresses`), we should include private IP addresses like 127.0.0.1. (Counter opinions welcome.)
(3) If a peer during discovery has a public IP that matches our public IP, maybe we should include private addresses for that peer? (Assuming we have the addresses now, but they are being filtered.)
