questions about results file created by pyCHX

Just a list of questions that we can add to and answer:

• What is the units of md['dectector_distance']? The values is 16075.637817382812

• What is qth_interest? It is an integer, so is it the number of rois?

• Seems there are some redundant md key values in the md dictionary. Are they all needed?
  Measurement versus sample
shutter_mode versus shutter mode
beg versus beg_OneTime versus good_start
end versus end_OneTime
  all the keys bringing with eiger4m.... for beam center and acquisition details and incident wavelength and so on
  acquire_period versus frame_time

• is md['time'] the time that the notebook was executed or results data is save to file?

• md[qr] is the same as qval_dict, except qval_dict is an unordered dictionary. Are both needed? Can we live with getting rid of one of these, and are there strong arguments for either @AbbyGi @xmchenGH this is important for NeXus file.

This may also be useful for @AbbyGi