Prevent `ITransport` from sending a `Message` to the same `Address` as `ITransport.AsPeer.Address`

[greymistcube]

There are several places where peers are filtered manually with something like

foreach (BoundPeer peer in peers.Where(peer => !peer.Address.Equals(_address)))

to sidestep sending a Message to itself. I think it'd be better to make ITransport throw an exception instead and make it part of ITransport's spec.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. Thank you for your contributions.