Coloraide

- **FIX**: Average should allow controlling `powerless` be disabled by default for backwards compatibility.
- **FIX**: HWB should use the algorithm defined in CSS that allows for round tripping even in the negative lightness
direction. Previously we were converting directly from HSV.

- **NEW**: Add `HWBish` mixin class.
- **NEW**: Deprecate `algebra.no_nan()`, `algebra.no_nans()`, and `algebra.is_nan()`.
- **NEW**: When averaging in a cylindrical space, always treat achromatic hues as powerless for better results.
- **NEW**: Add experimental support for CSS "powerless" hue handling and carrying-forward in interpolation, both
disabled by default.
- **FIX**: Fix RLAB conversion.
- **FIX**: Fix clipping of hues.
- **ENHANCE**: Tweaks to some matrix calculations.
- **ENHANCE**: Various performance related tweaks.

- **NEW**: Add Cubehelix color space.
- **NEW**: When precision is set to `-1` for string output, double precision (`17`) will be assumed.
- **ENHANCE**: More robust and generally better matrix inverse. Related inverse matrices have been regenerated for
consistency.

- **FIX**: Fix issue where `harmony` would convert some colors to cylindrical spaces and not properly consider order
of channels.
- **FIX**: XYB, while Lab like in its default configuration, has such a large disparity in the non-lightness
components that the ranges for them should not be the same when using percentages.
- **FIX**: Lab like space mixins should not try and order `a` and `b` like coordinates when calling `indexes()`, but
should return them in there current order with lightness first. The meaning of these components can be different
enough for a given color space to make normalizing their ordered configuration meaningless and alter inherit hue
direction when processing for `harmony`.

- **NEW**: Add new RYB color space.
- **NEW**: Add `Regular` mixin class for normal, 3 channel color spaces (sRGB, CMY, RYB, etc.).
- **NEW**: `harmony()` can now accept and transform `Labish` and `Regular` color spaces to cylindrical spaces.

- **NEW**: Add `padding` parameter to limit color scales when interpolating.