Fixed rescaling in correlation mode
Fixed rescaling in correlation mode

The correlation data needs a different rescaling factor to get values in
V.
Relates to #180.

DiCarloLab-Delft/PycQED_py3,DiCarloLab-Delft/PycQED_py3,QudevETH/PycQED_py3,DiCarloLab-Delft/PycQED_py3