tools for save files

[benknoble]

Since save files are FASL'd serializations, it would be nice to have some tools to

• "pretty print" a save file to an editable file (to make tweaks)
• "unprint" the editable version back to a (loadable) save file.

See #24 .

[benknoble]

Given gui/deserialized-state, I'm going to close this. It would still be nice to have an editable version, but I can live with what I have for now.