OO-449: move from ehcache to infinispan to have access to a distributed cache in a cluster environment, fix some issues with a cluster environment

OO-449: implements notifications for private message, download of log in course and group, archive of log by course deletion...

OO-449: refactor user session to work with identity key, make it pop, implements one to one chat, group chat, course chat, remove connect user list, refactor UserRequest to make it an interface

OO-449: first part of the implementation: remove smack libraries, refactor controller and unify them, implements messaging across the OpenOLAT event bus, implements administration part to enable chat...

OO-445: make the date in "Home > Subscriptions" mandatory and don't retrieve the news if there isn't a date.

OO-291: change the behavior of the buttons in "User admin > User > Groups > Add to groups". The search is activated by enter in the popup but not in the wizard

OO-433,OO-441: optimize data retrieval, save default values of properties which doesn't exist, check if the table controller is not disposed after loading start the data

OO-443: decrease level of the log to debug. If a user has not access to a resource, it's not an error

OO-438: fix an empty  select ... in () in the query to update the subscribers if there isn't subscribers to update

OO-436: enhance the method which check if a real email must be send. The method test the single CC too.

OO-435: overwrite the state saved in the course if the course is in the catalog but the state was saved as "no" (doesn't link it in the catalog) in a precedent publication

OO-418: add a workaround to the importer in one step which prevents to finish several time the course import