== CMark wrapped for Zig

This is https://github.com/commonmark/cmark[CMark] with a fairly bare bones wrapper
around it.

There exist pure Zig markdown parsers, so why bother doing this? The only up-to-date Zig
markdown parser is actually a port of the github-flavored-markdown fork of CMark, which
on paper does not appear to implement the 0.30 version of the commonmark spec
(despite that version being over 2 years old at this point). I also do not need or want
the GFM extensions, which are poorly documented. Ironically, one of the interesting
features (footnotes) is completely omitted from the "gfm commonmark spec", as far as I
can tell. Additionally, the pure Zig port is not dependency-free. It uses libPCRE to run the
regular expressions required by the parser, whereas commonmark has them pre-compiled to
C source with re2c.

Plus I wanted to have a markdown parser project with an Asciidoc readme.