Roadmap for 7.6 and beyond

I am currently working on the following features:

1. password-based key derivation [DONE]

2. HMAC-based key derivation (HKDF) [DONE]

3. authenticated encryption
   This builds upon #111, which I would like to (ideally) merge first.

These features will definitely be ready for 7.6.

For the next development series, I will implement:

• incremental encryption
  This will allow us to encrypt large files with library(crypto).

• certificate and key export
  This will allow us to create self-signed certificates from SWI-Prolog itself.

Other features are implemented as they become requested. If you need a feature urgently, please file an issue.