remove dependency on libpng++
remove dependency on libpng++

pimms/DeepCL,MiniLight/DeepCL,hughperkins/DeepCL,FighterLYL/DeepCL,Peilong/DeepCL,mrgloom/DeepCL,MiniLight/DeepCL,Peilong/DeepCL,mrgloom/DeepCL,mrgloom/DeepCL,mrgloom/DeepCL,mrgloom/DeepCL,MiniLight/DeepCL,FighterLYL/DeepCL,MiniLight/DeepCL,pimms/DeepCL,Peilong/DeepCL,hughperkins/DeepCL,pimms/DeepCL,hughperkins/DeepCL,FighterLYL/DeepCL,hughperkins/DeepCL,MiniLight/DeepCL,hughperkins/DeepCL,FighterLYL/DeepCL,Peilong/DeepCL,pimms/DeepCL,FighterLYL/DeepCL,pimms/DeepCL,Peilong/DeepCL