Based on SameBoy's "accurate modern" colour mapping.
Special thanks to @Rangi42 for her patience throughout development, @LIJI32 for researching the colour curve and helping with the creation of the reverse mapping (colour spaces are *fun*!), and @coffeevalenbat for testing :)
- Changes most `/* comments */` to `// comments`
- Changes `/**` block comments consistently to `/*`
- Adds consistent license comments to all files
Also renames `T_POP_SET` to `T_Z80_SET`
