#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.
I actually disagree with this suggestion.  

We used to do this kind of thing in GalSim, and Jim Bosch pointed out that this actually makes it harder to diagnose problems, since you lose the full trace.  The trace will show that the exception is happening through the applyNonlinearity function, so they can know that this is where it happens, but they also get the full trace of the downstream calls to better figure out why there was a problem.

So Jim recommended (and I agree) to pretty much never catch an exception just to repackage it with a new message and rethrow.  Just let the original exception go with the full trace up to a point where someone may be able to appropriately deal with it.