Feature debug logging

[yablacky]

To find out if the hue-app uses the https connection I added an debug option in order
to see the debug logging output. It can be used like this:

# stop it running as a service:
sudo systemctl stop hue-pass

# the deconz.service must run otherwise HuePass will fail:
sudo start deconz.service     # or deconz-gui.service, if you like

# run the hue-pass "service" standalone:
sudo ./HuePass.py --debug