Adjustments to the client

Most of the features are now in place.
Use the new client in the main app
Small adjustments in the way SOAPpy is included

All SOAPpy includes are now in AaptosSOAP.py
Put in place dummy classes for tests, bug fixes

DummyInstrument and DummySCPI are available to fake a powersupply when
no actual device is connected. They have to be activated by hand in both
AgilentE3631A.py and AgilentE3633A.py.

This allowed me to test the communication AaptosSOAP.py <->
AaptosCli.py.
Afer fixing few trivial bugs (and a couple of more serious ones), it
seems to work fine now.

Still untested: actual RS-232 communication and db logging.