The newer Racermate FTDI based USB adaptor (USB-StereoJack) failed
to receive data from the Computrainer, this was due to incorrect
flow control settings.
Fix supplied by Eric Brandt.
The docs for CreateFile indicate that to open a comm port above
COM9 you must use a filespec of "\\.\COMX". The original code
did not apply this rule and failed to open ports above COM9 as a
result. This is especially important since it is quite common for
the USB->Serial converters to assign an assignable comm port number.
