Add more image format types to gloperate::Image::channels().
Add more image format types to gloperate::Image::channels().

j-o/gloperate,cginternals/gloperate,hpicgs/gloperate,j-o/gloperate,cginternals/gloperate,hpicgs/gloperate,hpicgs/gloperate,hpicgs/gloperate,hpicgs/gloperate,cginternals/gloperate,j-o/gloperate,j-o/gloperate,cginternals/gloperate