Should Implement Wrappers (and Reader-threading) For Json-based methods

[micmarsh]

Will probably cover more real-world use cases. Can likely thread some kind of "json type registry" through with HttpClient as well. May need to get clever with inheritance(!?) to enable reuse of base monad and environment, but we'll see.

[micmarsh]

The kind of unfancy approach sketched out here 416f285 (provide basic deserialization and not much else) is probably just fine due to both time and complexity restraints.

Lightweight "lens-like" helpers for dealing with raw JsonElement types may also be a good idea, we'll see how real-world use cases play out.