They're either not needed or called automatically as needed
Previously reset would set max_bytes to 0 (unlimited), it now sets max_bytes to it's default of 2**30.
They only matter for XS
libpng synthesizes gAMA and cHRM chunks on input when sRGB is present, so ignore them if sRGB is present. No longer generate a png_text tag when the keyword is recognized. Added png_time