Add QoS to THNK messages

[arthuro555]

Some THNK messages might need to be received at all costs, some might be less critical. THNK should provide an option to decide whether or not the message should be sent reliably (e.g. re-send the message as long as it is not ACK by the server + ignore duplicates). Note that THNK will never provide a guarantee of messages being ordered, as that is a terrible idea for realtime gaming.