Quantization to 16 colors with none/Riemersma error dithering

16 Colors	16 Colors + Riemersma
Uniform (2,1,1)
RMSE 110.230	RMSE 158.703
Popularity (3 bits)
RMSE 38.275	RMSE 58.866
Median Cut (8 bits)
RMSE 25.443	RMSE 36.359
Octree (8 bits 2-pass)
RMSE 30.829	RMSE 40.199
Xiaolin Wu v2
RMSE 22.330	RMSE 33.700
Dennis Lee v3 (5 bits)
RMSE 20.800	RMSE 33.212
Binary Split
RMSE 22.199	RMSE 33.858
Lloyd (K-Means)
RMSE 20.800	RMSE 32.885
NeuQuant (200 cycles)
RMSE 20.994	RMSE 30.011
SColorQ
38.109