Krakel: A tiny 2d kd-tree ported from OpenCamLib

I ported this because I needed a lean, but still specialized kd-tree implementation.

License

LGPL2.1

Contributing

We welcome contributions from the community. Feel free to submit pull requests or report issues on our GitHub repository. Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the LGPL2.1, without any additional terms or conditions.