REFERENCE APP: CryptoRequest tool

[ChristopherA]

A command-line app written in RUST for experimenting with Simplex, UR, and CBOR concepts.

https://hackmd.io/@wolfmcnally/By2kv1uXc

We need a tool to make this sort of thing easier:

https://github.com/BlockchainCommons/crypto-commons/blob/master/Docs/crypto-request-test-vectors.md#appendix-standard-process-for-creating-test-vectors

To do this both directions, making and reading test vectors.