There are 2 changes -
1. Encode txPort in ttag packets and use it at TxTtagStats and
RxPcapStats to identify Tx and Rx packets respectively
2. Don't use pcap_sendqueue_transmit() if stream timing is in use -
since we can't modify TTAG packets inside that API
For now we are just debug printing timestamp with T-TagId and GUID. We
need to store this tuple and compare when we Rx the same - this will be
in a upcoming commit.
