Sync indicators on peer list

[hackergrrl]

This might end up being more of a cable-cli thing, but I was thinking it'd be nice to see some indication on the peers I'm connected with whether I'm fully synced with them, or still downloading/uploading. Unicode up/down characters? I'm not sure. I mention it because I've noticed there can be a delay of several seconds between peering and seeing new messages appear on my client, so it's not always obvious if I'm fully synced with my peers or not.