I think these are good functions to leave in -- especially the excel reader, which we don't otherwise support. I would just make sure there's a graceful fallback if pandas isn't present. We should also add a check to automatically create CategoricalComponents, along the lines of your old `np.all(np.isnan())` trick in `add_component`. I am fine with the logic of that test, but would prefer a method that doesn't create the np.isnan temporary array (sometimes I load huge memory-mapped images, and this temporary in-memory array will eat up RAM)