Add code linters and remove dead code

[aaaandrzej]

This addresses some of the points mentioned in [#33]:

• Fix flake8 errors
• removing dead code

Black should format the code in a way acceptable by flake8 when using current config. make lint-fix to be run against this branch once #41 is merged to avoid too many conflicts.

I probably won't be able to fix points 3-5 very soon so the question is if we want to merge it separately or whether the PR should fix all of the [#33] issues

[ClasherKasten]

Some little things:

• I would like to stick to single quotes instead of switching to double quotes
• Makefile is an idea, but setting up pre-commit would be a better option in my opinion

[aaaandrzej]

Single quotes seem doable, there's axblack fork of black that does that, I can add it easily. I won't be able to help with pre-commit hooks soon though, I'm afraid, as it looks like quite a big task itself. Would you accept a PR with formatting fixed, flake8 happy and dead code removed, or would you rather prefer for someone else to complete the whole [#33] at one go?

[aaaandrzej]

Note on the PR closure - I underestimated merge conflicts and decided to force push which closed this PR automatically, but my previous comment should be still valid.

[ClasherKasten]

Would you accept a PR with formatting fixed, flake8 happy and dead code removed, or would you rather prefer for someone else to complete the whole [https://github.com/marcusbuffett/command-line-chess/issues/33] at one go?

Every single step towards better code quality is welcome. So yes, I would also merge a PR with formatting corrected, happy flake8 and dead code removed.

I won't be able to help with pre-commit hooks soon though, I'm afraid, as it looks like quite a big task itself.

Then I'll open a new issue for this.