The correct determination of Windowed mode is critical to
maximise the speed on a USB based upload.
This commit bases the detection of a Serial (FTDI) on the
fact a CDC ACM port (USB) does not really have a baud rate.
We bump the baud rate to 233% of the requested baud rate to
see if the SYNC is acked. If it is Acked it must be a USB
port and Windowed mode is turned off. This removes unnessary
baud rate based delays from the proframing logic. If it is a
real Serial port getSync will not get the ACK and Windowed
mode is turned on.
f12acd7b0f