minor fix to normalize-by-median, cleanup of saturate

[ctb]

A few minor issues; note that saturate-by-median is in sandbox and so doesn't need to be reviewed particularly.

[ctb]

• Is it mergable
• Did it pass the tests?
• If it introduces new functionality in scripts/ is it tested?
  Check for code coverage.
• Is it well formatted? Look at pep8/pylint, cppcheck, and
  make doc output. Use autopep8 and astyle -A10 --max-code-length=80
  if needed.
• Is it documented in the Changelog?
• Was spellcheck run on the source code and documentation after changes
  were made?

[ctb]

I think this is ready for review. Anyone?

[mr-c]

LGTM, merged

[ctb]

excellent, thanks!