[PNG] Meeting topics

Hello everyone,

Now that Third Edition is out, we can resume our meetings to make progress
on Fourth Edition. We have a meeting this coming Monday.

Topics to discuss:

   - Gain maps / gain curves / T.35 / rWTm
   - IIRC we wanted to pause a bit for a SMPTE standard to be released?
   - Negative cHRM values
      - We already like the idea. Just need to make an edit and possibly
      add a note that a decoder may have accidentally assumed the
unused sign bit
      would be zero rather than ignoring the bit.
   - Non-normative recommendation for decoders that encounter broken PNG
   files.
      - I think there is already some wording for this? I seem to recall
      bumping into this early on in Third Edition work.
   - pigz-style parallel encoding
      - I have no updates here. I was working on it but dropped it. I'll
      pick it back up soon.

See you Monday!