OO-3189: make the link to about page static, remove the invisible logout link from the index page, cannot open several times the about page without closing it, fix a memory leak in high score

OO-2844: add option to show the full text search to guest users, update check access of the different indexers, remove the context aware full text search in forum if the option is disabled

OO-1658 implement HelpTooltip componente to use the new form context help also outside of the form context

OO-1739: backport the delete button in file element and use it in user profil for the avatar, in the resource description and in the catalog entry editor

OO-1635,OO-722: refactor the ajax by iframe to use XHR, push the current business path to the browser via HTML5 push state, implements back button support via HTML5 History API...

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