reStructuredText (http://docutils.sourceforge.net/rst.html http://docutils.sourceforge.net/rst.html) seems have all those qualities. It's simple and IMHO more c

reStructuredText (http://docutils.sourceforge.net/rst.html http://docutils.sourceforge.net/rst.html) seems have all those qualities. It's simple and IMHO more consistent than Markdown, math and include directives, cross-references and can be compiled to almost anything with tools like Pandoc (http://johnmacfarlane.net/pandoc/ http://johnmacfarlane.net/pandoc/).