Marathon: massive pull request with all the developments for the marathon

I'd like to get this all back on the master branch, if people agree... of course, it'll mean a lot of changes being pulled in. This is to start the discussion if we want this or if we want it to remain in its separate branch. As most of the web stuff for the marathon is in a subdir `apache` the impact should be too severe. the top-level is pretty much unaffected. Please check and send your comments on this.