[PNG] Upcoming meeting topics (Fourth Edition)

Hello everyone,

We are cutting a feature branch for Third Edition and continuing work onto
Fourth Edition.
So our topics for discussion are Fourth Edition items:

   - negative cHRM values
   - Inserting deflate restart markers into a stream where a new scanline
   with compatible filter allows -- add new chunk to indicate the location of
   those restart markers
      - possibly also not at scanline w/ compatible filter locations --
      we'll want to gather information on deflate decode time vs.
other png work
      time to see if parallelizing just that portion is worth it
   - Compression methods other than deflate
   - Gain maps
   - Generic image data
   - dWLm

Possible other topics which have been mentioned but aren't in a Github
issue:

   - Boundaries other than scanlines. For example, blocks.


There are probably more topics I'm forgetting right now. Feel free to reply
with them so they get included. But this will be more than enough for one
meeting. :)

See you Monday!