GEOT-4540, Error rendering very simple transparent 8 bit PNG images
 GEOT-4540, Error rendering very simple transparent 8 bit PNG images
GEOT-4540, Problems with 4 bits paletted imagery
GEOT-4540, Problems with 4 bits paletted imagery
Merge pull request #256 from simboss/9.x-up

 	GEOT-4540, Error rendering very simple transparent 8 bit PNG images