Only consider USB NI oscilloscope devices...
Only consider USB NI oscilloscope devices...

Only consider USB devices when scanning for National Instruments
oscilloscope devices.  This is necessary, since *any* `COMM` port
is recognized as a device by the Python `visa` library, causing false
positive detection of an oscilloscope when there is no scope present.

wheeler-microfluidics/dmf-control-board-firmware,wheeler-microfluidics/dmf-control-board-firmware,wheeler-microfluidics/dmf-control-board-firmware,wheeler-microfluidics/dmf-control-board-firmware