I tried to follow the 80:20 rule, as the transformation is a throwaway thing.

Open issues to be manually fixed:

- nested lists need handwork. A comment is generated
- some combinations of * and _ could not be converted properly

Xdoc issues:
- Java references don't work
- blank lines around section statements are somewhat tedious
  - a document cannot start with a newline and a new section or end with a section and a newline.
- empty texts should be allowed, e.g. for td[]



