OO-373: made the notifications manager robust under concurrent access, write more unit tests to tests the queries on the database and test it under concurrent load

OO-293: better back support while switching between static sites and enhance the check for the mapping site <-> history point by adding a real business path

OO-293: better back support in course (run), better switch between sites and dynamic tabs, better behavior after closing a tab (stack of previous tabs/sites not limited to 1 site)

OO-291: add english translations, replace tutor wording by coach, in course membership switch to the "All" tab after adding a member, in the list of memberships disable the checkbox for waiting list if not available

OMA-87: enhance the REST API for notifications, add more informations about forum and folder notifications

OO-364: make the access to the autocomplete search of users configurable in the standard controller and in the forum

OO-369: make an interface for the StackedController, add some translations, refactor the course db main panel

OO-291: update the bulk changes / user import ... to use the new methods of the business group service

OO-291: fix load for update for PostgreSQL, fix unit test for course group management (always consume entity before queriying the database!), fix the statistics rights in the course view

OO-291: remove doInSync in BusinessGroupService and use pessimistic locking directly on the BusinessGroup