Moved two LUTs to PNG_IO.Base
Moved function Hex to PNG_IO.Base.To_Hex_String.
New child package
New program
Added 'with' for PNG_IO.Base and some declarations moved to PNG_IO.Base.
Removed assertion checks (now in png_io.base.ads)
Read file signature in one call, and compare in one comparison.
No. to NO in sRGB report