Upgrading several dalek dependencies and rand

In order to update the dalek-cryptography dependencies, an update to the zkp library is required. I'm looking into the best way to handle this for the future of Lox. In the meantime, I've made a private clone of zkp, applied the dependency updates and have got it working with the other updated libraries. This will be WIP until the issue with zkp is resolved. In the meantime, I will close !45 (closed) !46 (closed) !40 (closed) and !38 (closed) as none can be completed without the changes to zkp.