make convert_from prototype accepts several arguments (to build command with several arguments)

Some improvements & cleanups. Now the get/set mecanisme using descriptor works (but is not yet implemented for most commands of the HP356X devices).

Try to be a little more robust when instanciating the GPIB class (serial connector)

(0) -30 -10 -3 +3 +10 +30 tip

mercurial