Better README

[jayvdb]

The README is a bit vague. :P

It looks like this package intercepts module imports, and invokes a callable.

But does it need something like https://github.com/absalon-james/os_usage/blob/0a64bde18f21ce5f3310ded5a9acf6f22df07b26/etc/os_usage/sitecustomize.py to activate it with sys.meta_path?

Does it need to be in sitecustomize?

The notes at https://github.com/absalon-james/magic_the_decorating/blob/17da750/magic_the_decorating/importer.py#L78 look like README material.

I am especially interested in the loaded modules need to have __file__, as I am looking for a way to add __file__ to modules loaded with PyOxidizer (c.f. indygreg/PyOxidizer#69) but have control over the value added.