Add chicken scheme libraries (#198)

* README.md (Scheme): Add "crypto-tools"

* README.md (Scheme): Add "crypto-tools".

* README.md (Scheme): Add "chicken-sodium"

* README.md (Scheme): Add "chicken-sodium".

README.md

@@ -406,6 +406,8 @@ encryption library providing MD5, SHA1, SHA2 hashing and HMAC functionality, as
 
 ### Scheme
 
+- [chicken-sodium](https://github.com/caolan/chicken-sodium) - Bindings to libsodium crypto library for Chicken Scheme.
+- [crypto-tools](https://wiki.call-cc.org/eggref/5/crypto-tools) - Useful cryptographic primitives for Chicken Scheme.
 - [guile-gnutls](https://gitlab.com/gnutls/guile/) - GnuTLS bindings for GNU Guile.
 - [guile-ssh](https://github.com/artyom-poptsov/guile-ssh) - libssh bindings for GNU Guile.