Polish mediapy_examples notebook

[hhoppe]

Created a mediapy_examples.py file that mirrors the mediapy_examples.ipynb notebook (using jupytext).
Running lint tools on it suggested several small improvements.

Got the package to also work on sys.platform == 'win32'; this only involved updating one test.

[Conchylicultor]

Thank you! I sent this for review

[hhoppe]

@Conchylicultor Could you please have a look? Thanks.

[Conchylicultor]

This was merged internally, but somehow copybara didn't push to github. Will investigate

[Conchylicultor]

Sorry for the delay. Should be fixed once #46 is reviewed and merged internally

[Conchylicultor]

The other PR was marged but copybara didn't automatically close this PR.

Otherwise, it looks the release failed with : https://github.com/google/mediapy/actions/runs/9284368143/job/25546671814

ERROR    HTTPError: 400 Bad Request from https://upload.pypi.org/legacy/        
         User 'mediapy-owners' does not have a verified primary email address.  
         Please add a verified primary email before attempting to upload to     
         PyPI. See https://pypi.org/help/#verified-email for more information.  

I'm not sure who own mediapy-owners. I tried to contact the group. I hope they still have access to the password

[Conchylicultor]

Last version was published. I think things are green again: https://github.com/google/mediapy/releases/tag/v1.2.1