Draft: psd: Add support for 8-bit depth CMYK image
Add support for display basic 8-bit depth CMYK image. The software I'm currently using seems cannot export 8-bit CMY or 16-bit CMY/CMYK/CMYKA formats, so only 8-bit CMYK for now.
Unit tests weren't added, might add later. I'm still not very sure about my implementation is okay so please help review the code. Thanks!
Edited by Gary Wang