Implements toc extraction. Refs #16.
Enables generation of toc markers for md headers. Refs #16.
Generates index file from markdown HTML. Refs #16.
Extracts header id attribute to link stuff properly. Refs #16.
Adds proc to extract properly all child text. Refs #16.
Documents task in changes log. Refs #16.
Merge branch 'feature/t16_md_index'