As the repo says it uses CodeKit to pull everything together from build into app. Then you simply put the contents of app online via ftp. The older php based site is also on the ftp at /2012/ - so it would be hard to move to gh-pages, though it would make it much easier.
The CodeKit tool does the LESS processing and also compiles the html from the .kit files.
The repo also has the compiled HTML (/app) - and if we wanted to move away from CodeKit one could simply start working directly on the compiled pages.
Alexandre, I did make the changes the other day you asked me to make - though I did leave a ref to 2014 eu show, because I had already promoted it and wanted people to know the change of plans.