Despace

1. Added pre-commit hooks so that `flake8` and `mypy` checks are no longer in the `tests.yml` Github actions.
2. Removed `examples` and moved the images into `images`.
3. Initiated `docs` using sphinx.

pre-1.0
Implemented 2D Hilbert type space filling curve and data sorting.

Some milestones for the project reached:

1. Add test cases for sorting and plotting.
2. Add Github actions for testing on `ubuntu-latest`, `windows-latest`, and `macos-latest` platforms for python 3.6, 3.7, 3.8, and 3.9 versions.
3. Remove `_flatten` function because it's not really needed.
4. Minor changes to comply with `flake8` and `mypy`.

1. Add colab examples
2. Clean up

alpha
1. Reconstruct code base so that it's more like a serious project.
2. Convert previous scripts and functions to a python `class`.
3. Add more control for plotting.
4. Add tests and examples.

2D and 3D cases are implemented and tested with examples included.

What's Changed
* project description by Ruibin-Liu in https://github.com/Ruibin-Liu/Despace/pull/1

New Contributors
* Ruibin-Liu made their first contribution in https://github.com/Ruibin-Liu/Despace/pull/1

**Full Changelog**: https://github.com/Ruibin-Liu/Despace/commits/0.0.1