Split helper.py into parts
PR 1/3
helper.py is getting too long for a function dump. it is now split into several constituents based on some loose themes. rest of the code is updated to import from these parts.
run_hh.py also gets an extra option to restrict the processes being run to just a handful (useful e.g. for gen studies).
run_combine.py is updated to allow limit running in multiple parts, and a mode to merge the results. argumentative.py, hilfemir.py are updated for the extra options.
desalinator.py is cleaned up because the comment applies to another repo I took the script from.