Create algorithm to reprocess REFL data

[Mathieu Doucet]

We need an algorithm to re-reduce the data of a given IPTS.

[Mathieu Doucet]

Re #7961 Add reprocessing algo

Changeset: e94220891d42bc5a17ec26284c4e77e531f3a05a

[Mathieu Doucet]

To test: Part 1:

• Load your favorite REFL reduction file (.xml) into the REFL reduction UI.
• Save it in an empty directory (so you can delete it after you are done testing).
• Copy your saved reduction parameter file (.xml) into that directory.
• Start the REFLReprocess algorithm UI.
• Enter the directory path in the "IPTS" field AND the OutputDirectory field. Leave everything else blanked and unchecked.
• Hit Execute. The algorithm should read your file and execute the reduction.
• The reflectivity for each run should be saved in a separate ascii file in your new directory, along with the stitched reflectivity.

Part 2:

• Restart Mantid
• Start the REFLReprocess algorithm UI.
• Enter your new directory path into the OutputDirectory field.
• Check the LoadProcessed box.
• Hit execute.
• The reflectivity curves that were saved in that directory should now be loaded.
• Start the REFL reduction UI and load up the .xml file with the reduction parameters.
• The reflectivity data should automagically stitch itself.

[Michael Reuter]

Merge remote-tracking branch 'origin/feature/7961_refl_reprocess_algorithm'

[Stuart Campbell]

This ticket has been transferred to github issue ​8806