OO-2515: save the master file untouched, deliver  more pixels for the print view of the members course element, add REST api methods to check if a particular size of portrait is available

OO-1819: add param for inital author, add param to not set the initial author, return more infos for course members

OO-1616: fix the certificate unit test in the REST API suite, don't doInSync during import of the course, remove get resource method (duplicate), remove unused constructor and method

OO-1770, OO-1769: allow pseudonym and guest posts, refactor the message model to hold only threads or messages of a unique thread in memory, minimize the number of joins on query, minimize the number of queries on peekview, remove buggy docking feature...

OO-1616: replace the view for the business group lists with several customized queries which load only the needed data

OO-1616: reduce the number of double call to the repository entry with the manager and after with the course

OO-1645,OO-1595: refactor the personal configuration of calendars, the datamodel of imported calendars, make the description visible and editable...

OO-1615: springuifie mail package, rest package, question pool module... remove unused dependencies...

OO-1443: upgrade JUnit ( long overdue ), remove deprecated junit.* packages, fix some issues with order dependent tests, fix an issue with empty ClusterDoInSync