For module in idlelib modules:
    Create test_module from new template.py.
    Add 'module' to docstring and import.
    Check other minimal imports.
    Create instance of each class, with requires('gui') if needed.
    Add initial coverage of this test.

I am also reviewing existing tests.

PR initially adds template, 1 new file, and edits 3 others.  Needs blurb.   I will add more, but will likely break this up into multiple PRs.  This should, of course, been done years ago.

Reviews welcome, non-Windows test would be good.  (Tal, what do you have?)