Cookie now contains the dht public key of the peer which makes
more sense than including the real public key of the reciever.
It means we no longer have to rely entirely on onion_client to
find the dht public key of the other peer.
There should be no more delay between a peer closing their client
and their friend being notified of them going offline. (unless the
kill packet is lost)
Wrote down more of the protocol.
Padding support has been added and implemented which will make it
possible for us to pad packets to mitigate length related attacks.
