message: core: do blocking read on serial port
  We should be able to read in a blocking way on the serial port since it
  happens on a separate thread.
diff: @@ -66,7 +66,7 @@ DroneCore::ConnectionResult SerialConnection::setup_port()
  bzero(&tc, sizeof(tc));
  - _fd = open(_serial_node.c_str(), O_RDWR | O_NOCTTY | O_NONBLOCK);// | O_NDELAY);
  + _fd = open(_serial_node.c_str(), O_RDWR | O_NOCTTY);
  if (_fd == -1) {
  return DroneCore::ConnectionResult::CONNECTION_ERROR;
  }
  