Make the key optional in crypto_generichash (blake2d)

See CHANGELOG

Complete fork for Paseto libraries

Forking original library with fixes (#2)

* Forking to libsalty2 as original is no longer maintained

* Updating mix and README

* Update README.md

* Updating exdoc

* Changing some stuff

* Change nif loading

* Starting teh application so that the nif loads automatically