README in data folder should be updated?

[BethanyRS]

This isn't anything urgent. However, within the pahfit/pahfit/data folder, the README contains extra information about the ISO-SWS data, but not about any of the other data within the folder. For consistency, it might be nicer to have the ISO-SWS information in the ISO_SWS subfolder, or to add more information about the other data files to the README.