Add shared Settings and Examples GUI

[Poikilos]

Hello, I hope adding a GUI is helpful as discussed, and that this is in order. If I broke anything we can look at that, but I think all known issues predated the changes (See "Tasks" below).

Added

• GUI to select settings for examples.
• A Settings class that saves settings.json (added to .gitignore). It is defined in examples_settings.py.
  • Makes it so the settings in the examples aren't hard-coded.
  • The hard-coded values have been moved to the DEFAULT_SETTINGS dict in "examples_settings.py"
  • Facilitates another program (GUI in this case) changing the settings before running an example.
  • In the near future, I could make the examples modular (put everything in classes or functions, and enable setting our own callbacks). That way, they can be imported instead of running in subprocesses.
• Filled in some instances (and added more & filled in more) of _type_ and _description_ in Google Style docstrings (which Sphinx can process to generate documentation; Google Style defines thorough type and class attribute documentation).

Changed

• Use PEP8 more by changing spacing in a number of cases (This facilitated flake8 [or pylance and ruff in Visual Studio Code] finding a couple actual errors while not having excessive output--see the note directly under "Tasks" below).
• Ignore some PEP8 spacing rules to match the program's current style (the --ignore flag for flake8 found in python-openlcb.code-workspace can also be used with flake8 when running it from a terminal).

Fixed

• Unused substitution in formatted string.

Tasks

See FIXME statements in code. One or two more were added since flake8 or pylance found some issues but I wasn't sure how to fix one of them. I'll need your help on these.

• 33

• 34

• 35

• These issues predated the PR, so merging is safe.

[bobjacobsen]

Thanks for all this! I'll work on the outstanding items this weekend.