request to add roc vd(unreg) readback to the gui

[werdmann]

It would be highly desireable to display the readback values of the unregulated digital voltage and analog voltage (with somewhat lower priority) to the gui.
A useful minimal display would be the average of the 16 ROCs. A more luxurious version could display all values in an extra tab or pop-up window.
Obviously this will only work for v21 and higher and should be greyed out for other ROCs or in case of readback errors.

[simonspa]

The pxarCore function

daqGetReadback();

automatically collects readback data when decoding incoming raw data. After every test or DAQ you can call the function and it will return all values stored, one vector per attached ROC.

In case of older ROCs or decoding problems you will just get an empty vector.

Plotting this should be rather straight forward I guess. Also @vtavolar wrote some code in PixTestReadback which makes use of this function, calibrates the voltages and plots them.