Cryptolens Client API for Rust

This library is currently in a beta release.

This library simplifies access to the Cryptolens Web API from the Rust programming language.

Several examples are available in the repository at https://github.com/Cryptolens/cryptolens-rust-examples.

As long as the library is at version 0.0.X we are not following semantic versioning. Before moving to version 0.1.0 at least the following needs to be implemented:

Parse server message when an activation fails, and return an appropriate error.
Add proper management of errors in third-party libraries.
Decide on how to deal with time, should we depend on e.g. the chrono crate? Or should we just expose the time as an integer and let the user deal with this as we do now?
Possibly change capitalization of names to make them more rust-like