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-1000: implements upgrade path for portfolio maps and group rights, test the upgraders for a large set of data

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