Serial port interface on frame grabber

[Josh Doe]

Camera Link is a scientific/engineering video interface that provides
for sending/receiving data over an embedded serial comms port,
typically for changing properties of the camera like exposure, white
balance, etc. I'm not sure if anyone else has interest in this, but I
was thinking of creating a GInterface perhaps named GstSerialPort for
standardizing this.

The two hardware APIs I've looked at so far provide two functions,
read and write (though one also provides a flush function). Baud, stop
bits, etc. are all defined by the Camera Link standard.

-Josh