NKeys support for Zig

Still a work in progress, things will definitely change!

Contains a tool called znk which is a clone of the nk tool.

Building

Zig master works at the time of writing.

Use zig build znk to build the znk tool. The znk tool can be run by using zig build run-znk.

Tests for the library can be run by using zig build test. Tests for the znk tool can be run by using zig build test-znk.