PetitMarkdown

I have implemented a PetitMarkdown grammar for PetitParser according to the CommonMark 0.19 specification (http://spec.commonmark.org/0.19/). The current implementation can be loaded like this:

Gofer new
    url: 'http://smalltalkhub.com/mc/JanKurs/PetitParser/main';
    package: 'PetitMarkdown';
    load.

The result of the parsing is AST, so I guess there is a possibility to write a CommonMark -> Pilar AST transformation. I wrote the AST->HTML visitor only.

CommonMark uses two pass strategy. The block elements are recognized in the first phase and the inline elements in the second phase. My implementation handles the first phase without any problems, there are some issues with the priorities of inline elements and emphasis (I don't understand, why more than 50% of the whole specification covers this). There are  in total 550 example, the current implementation handles 420 of them so far. I guess for the most users it handles more than enough,...