Inspired by @kiil, this PR adds another game for exploration &
inspiration - this time, based on the seminal incremental idle game
[Universal
Paperclips](https://www.decisionproblem.com/paperclips/index2.html).
This game implements a screen drawing loop with a roughly 60FPS
framerate, asynchronous user interaction via the new `job send` and `job
recv` commands, rudimentary deltatime calculations, and the ability to
save and load state memory.
The game does not feature any of the special mechanics that emerge from
the original, though a future project may emerge to make a more 1:1
replica of the original.
I have also updated the .gitignore to make sure no one accidentally
pushes their game save to the repo after trying it out. 😃
1. double pathsep when displaying PWD
2. error 'not a git repo' when PWD outside a repo (`do --ignore-error
{}` no longer eats the stderr text?)
3. improve display when terminal quite narrow (not a regression, just an
improvement)
4. reduce overhead for padding
I made a `toolkit.nu` with a very bare bones struct, this is called via
[`setup-nu`](https://github.com/hustcer/setup-nu) action, and generates
the `check-files.nu` file. After that, another nu instance run that
script to check files one by one. The folder `before_v0.60/` is
excluded.
