Fixing imageWorker check on PNG ImageWriterSpi availability
Merge branch '9.x' of https://github.com/geotools/geotools into 9.x
improved PNG writing for ImageWorker
Merge branch '9.x' of https://github.com/geotools/geotools into 9.x-final
GEOT-4540
finishing touches from testing on linux
GEOT-4540, Error rendering very simple transparent 8 bit PNG images
Merge pull request #253 from simboss/9.x-final

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