Wiki session list

The 'program' page for stateofthemap.org is now powered by a new wiki mirroring mechanism, pulling content from the OpenStreetMap wiki for the session list itself and also for session detail pages (of which there is currently only one example). Links between them are rewritten accordingly.

Changes made on the wiki will be reflected on the stateofthemap.org site, thus allowing everyone to add more details (e.g. links to slides/photos/resources on a session description)  Wiki content is cached for a short period (just 60 seconds) to alleviate any possible traffic problems.