Unravel Energy Calibration

[steinnymir]

The processor.energyCalibration method is now growing quickly with many different corrections applied together. These should be separated in different methods, so that they can be tested independently.

Might be a good idea to make functions which do not live inside the processor class, but in the processor.utilities.calibration. These should be functions which all follow the same structure, so that debugging them would be easier.

Such a re-structuring would be good to define for all calibration methods, no matter how simple they might be (see pumpProbeTime calibration)