#552 Detector non-linearity and reciprocity failure

A basic method to apply any desired non-linearity on an Image has been included to begin with. The non-linearity can be specified by a LookupTable or as a function, possibly with parameters, that can act on NumPy arrays. In addition, it also includes a feature to correct for reciprocity failure. A basic unit test to test these functionalities have also been built.
Yes, it’s true that exptime would have to include a gain factor, but that’s not too hard to handle.  So I think we can just say that (either the units should be e- or, if ADU, then the gain has to be folded into the exptime).=