Option for encoding sum types as insensitive strings?

[justinwoo]

Maybe awful, but I think maybe having an option to encode sum types by their constructor name could be nice, but the responsibility would be on users to not mess up with trying to add arguments. Thoughts?

[paf31]

We could add it as an option to SumEncoding, or even better, make SumEncoding into a pair of functions for encoding and decoding.