And API docs

It is stored on redemption and regurgitated by the Python APIs and dumped in
the JSON accessible via the HTTP API.

Runtime performance at 512000 is somewhat intolerable.  Further work is needed to support that scale.

We don't need to mess with the Python stack limit.  The proof is validated in
Rust.  We just need to offer more stack space to the Rust implementation.

That is, dumping any extra information from Hypothesis clutters up the test
runner output too much to leave this on in general. :(

No good trying to log 512000 tokens