Quantization to 16 colors with none/Riemersma error dithering

16 Colors	16 Colors + Riemersma
Uniform (2,1,1)
RMSE 115.057	RMSE 159.724
Popularity (3 bits)
RMSE 26.273	RMSE 33.752
Median Cut (8 bits)
RMSE 18.490	RMSE 25.277
Octree (8 bits 2-pass)
RMSE 25.154	RMSE 34.356
Xiaolin Wu v2
RMSE 15.830	RMSE 23.492
Dennis Lee v3 (5 bits)
RMSE 15.551	RMSE 22.576
Binary Split
RMSE 15.661	RMSE 23.654
Lloyd (K-Means)
RMSE 15.126	RMSE 23.530
NeuQuant (200 cycles)
RMSE 15.296	RMSE 22.479
SColorQ
RMSE 28.988