beautify with clang-format

[MFTabriz]

I ran clang-format 16.0.0 on the .cpp and .hpp files (with --style=file --fallback-style=none flags).

[grafikrobot]

1. The examples are formatted manually for easier reading in the documentation. And should not be changed.
2. The tests are mostly manually formatted to be easier to edit.
3. I've previously tried to change the tests to allow for using clang format. So that's a work-in-progress.
4. The single header is generated and should not be post formatted after generation.