Review and cleanup documentation

[zulus]

Long time ago i transformed old manually managed HTML documentation into markdown and automatically indexing process, but it need more polishing.

For easier management, we probably should abandon rhino+wikitext transformation and introduce asciidoc or sphinx. As an example see asciidoc tutorial, sphinx have even more functions: https://www.vogella.com/tutorials/AsciiDoc/article.html

[zulus]

Another reasons to use asciidoc:

1. GitHub gave built-in processor, see example gist : https://gist.github.com/dcode/0cfbf2699a1fe9b46ff04c41721dda74
2. On marketplace we can nice eclipse editor
3. Already exists maven asciidoctor plugin, so no more rhino!

@tbl0605 what you think? Only problem I have right now is howto generate list of ids, and convert it into helpContext.xml