Chunk menu more at page-level, except for Guide/{Concepts,API conventions}
"Coming soon" fixes
Leaderboards and Challenges menu entries lead directly to ./concepts
Fix get-include-infos.awk to unwrap formatted asciidoc titles
No link on menu for folder nodes that don't explicitly link on page
Add slight margin between ToC and text
change size & style of headings
add white margin around toc
change style of H2 in getting started pages

H2 are numbered and not underlined
Add breadcrumb