All steps now work from command line

todo: test appending all records to a single file, instead of
autocalcing from input file
Append to single out.csv test: kinda sorta notreally

The appending works, header rows are duplicated. They aren't removed
with remove_dupes() because some files have different columns. This
means we'll need more care to read and write each file... sigh, not done
yet!