"HCL" can refer to different things

[makew0rld]

I'm writing code to bring HSLuv to go-colorful (see #41), and I noticed that term "HCL" is used to refer to the cylindrical transformation of CIELAB. But as Wikipedia notes, the term "HCL" is very ambiguous. Furthermore, the use of cylindical CIELUV is much more common, and go-colorful does not have support for this.

I am going to be implementing cylindrical CIELUV (aka CIE LCh(uv)) as it's required for HSLuv. But I'd like to recommend that all functions using the term "HCL" be deprecated, and new ones be created that use a more accurate term - perhaps LabLCh is good? Or LabCylinder?