Check RTS/CTS status in case of send timeout

[rambo]

And maybe wait a bit more ? (or check CD or similar that Lotta is actually there)

[tanelikaivola]

Is this supposed to mitigate a failed send?

If so, this should be fixed by sending stuff line by line and terminating immediately if CD drops.

[rambo]

And general flow-control, I'm fairly sure pyserial already waits for CTS if rtscts=True (either forever or until set timeout) but as discussed yesterday we definitely should wait a moment (maybe 500/bps seconds ?) after each line and check that CD is still asserted before continuing. If we lose CD then abort and show error to user.

http://pyserial.readthedocs.org/en/latest/pyserial_api.html#serial.Serial.write says it raises SerialTimeoutException if it times out (due to CTS for example)