Changes:
- Separated formulas for RYB conversion and subtractive mixing into their own header and source files (RYB.h & RYB.cpp). They can now be used in stand-alone fashion either with or without Raylib
- Added, by request, a colorblind mode to facilitate palette selection for those with various color vision deficiencies (protanopia, deuteranopia, tritanopia or achromatopsia)
- Added color sampling functionality -- the "pick color" button
- Changed some font sizes for better legibility
- Simplified some of the code in formulas for better legibility (same functionality)
- Developed the README.md document further