OO-2610: allow no correct answers, better update of score label after changes, better read only mode like FIB

OO-2653	: make the css delegate transient (it hold the window which can lead to serialize the whole memory through tomcat binding)

OO-2648: path to the attachments of an assessmentItem are relative to it and not the storage folder (imsmanifest.xml) created by the question pool

OO-2626: change behavior of cache, add a lot of course node indexers, fix issue with Open document indexer, remove cache in search controller, add the filename (without suffix) if not title in meta information found, add a batch of XSD in blacklist...