OO-1016: better debugging of e-mails, don't send user info to factory for drop box subscription's context

OO-937: english wording, fix issue with checklist where passed is calculated from the number of checkbox

OO-1049 grand admin/moderator rights also to co authors for open meeting course elements (patch from Stephan Clemenz)

no-jira: backport fix for the escaping of already escaped characters by TinyMCE in enrollment course element

OO-1038: better check of long without exception, try and catch in PersistingCourseGroupManager, unit tests

-no-jira: replace escaping with antisamy for group description as the description is edited with TinyMCE (which already escape special characters)

OO-716: replace the flot library in the course statistics with the bar chart component which use d3.js