Raw Data Separation

https://git.xfel.eu/gitlab/roscar/karabo_data_interactive/merge_requests/5#note_98572

If you detect that the data is raw, you present the data as if it was separated into image.data and image.gain. This is reasonable, but maybe it would be better to be transparent about what's really in the file, and call them something like: image.data[:, 0] (data) and image.data[:, 1] (gain).

Not too sure what you mean by that? Started this as a separate issue since I'd like to merge the previous request