OO-936: implements course element "check list", enhance the flexi-table with sort, filter and export, enhance publish process with an update step, upgrade pdfbox to version 1.84

OO-934: the efficiency statement event must redraw only the link to open the efficiency statement and not the whole page

OO-948: make the ContextEntryControllerCreator cloneable, a cloned creator can save request dependent informations between the calls of the different method to prevent multiple loading of the same resource, calculate severals time the permissions...

OO-938 remove old code that tried to support escaped comments, does not work with column selection anymore.

OO-929: remove version on UserCourseInfos (move from optimistic locking to last commit win), rewrite the update method, refactor the UserCourseInfos mapping to use annotations

OO-911, OO-912: implements the course node triggered buttons in assessment tool, implement bulk upload for tasks with selection of a group if needed

OO-852: add a sequential queue for to the task executor to prevent simultanous bulk assessment task (which cause StaleObjectException)