Polar intervals make no sense

[maloleroy]

Describe the bug

Both the implementation and the tests on polar intervals make absolutely no sense and are incorrect.

To Reproduce

Despite the tests passing, a few hand-tested examples will show you how the current implementation just doesn't work.

Expected behavior

• a | b is the smallest polar interval that exists such that a and b are subsets of a | b
• The norm of a polar interval is equal to its maximal amplitude ("range") multiplied by its "angle delta" (expressed as a ratio, 1 being a full 2pi radiants / a full circle)

Additional context

I still don't have a definitive theoretical answer, so it's more a matter of maths work than a matter of C++ implementation.