File fomats

[hoodmane]

I think it's time to define some file formats so that we can ensure interoperability between different programs. As I have described before, we need two file formats:
(1) A JSON format for "front end data"
(2) A binary format for "back end data"

I will make a new github repository for the file formats because they are related to multiple git projects (latex spectralsequences, js_spectralsequences, and rust_ext) and describe what we need to do in more detail there.

[hoodmane]

https://github.com/hoodmane/spectralsequence_file_formats