Fix USB comm. to Yoko
Fix USB comm. to Yoko

Use python-usbtmc instead of pyvisa, where (in linux) every query after the first is refused. Ironically, with usbtmc the first write/query fails (see try-except block), but the following ones work fine. --DR

BBN-Q/Auspex,BBN-Q/Auspex,BBN-Q/Auspex,BBN-Q/Auspex