This PR fixes #81 and adds a new flag which lets you skip some files based on regex. Sometimes people keep testing files in the game and I don't want to delete them when running the code, I want to skip them by passing some argument to the program
There are multiple ways to do it, but I feel like using regex is the simplest, because you can skip arbitrary amount of files just by passing single regex.

And regarding the boolean flags, the only way how to pass them false value is using =, which is non-intuitive, so I added example to the readme. See the docs: https://pkg.go.dev/flag which say -flag x // non-boolean flags only

I have tested it locally and it works well.