Updated Dokeos 1.8.5 page

I've updated the Dokeos 1.8.5 page to reflect the fact that we now have a Release Candidate and are very close to the stable release. This is a time for us (developers) to take a deep breath and analyse things with the satisfaction of someone having done a nice job. Nevertheless, we are very careful not to miss anything, but as usual we count on your help to spot things that really are difficult to see. We are already thinking about the developments for 1.8.6, which will be only a few and will concentrate (if everything goes as expected) on exercises - making it easier and more reliable to build exams using Dokeos - and web services - making it easier to connect Dokeos to other web systems.