v1.1

• Significantly improved conversion performance
• Switched from using CIE2000 delta-E perceptual distance metric to Euclidean distance in CAM16-UCS space. Image quality is improved, it requires much less precomputed memory (192MB cf 4GB for the 8-pixel colour mode!) and is much faster at runtime. Win-win-win!
• Removed support for 140px conversions since these were only useful to show why this is not the right approach to DHGR
• Add support for modifying gamma correction, which is sometimes useful for tweaking results with very bright or dark source images.
• Switch default to --dither=floyd, which seems to produce the best results with --palette=ntsc
• Various internal code simplifications and cleanups