DUNE Hardware: added interface to set input and output line terminators.
DUNE Hardware: made expectOK() virtual on HayesModem.
Transports.GSM: disable echo on initilization.
Transports.IridiumSBD: disable echo on initilization.
Vision.DFK51BG02H: replaced int with size_t.
DUNE Network: added doFlushInput() to TCPSocket.