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

OO-1014: give the right name to identify the type of image in the repository details, fix the "grayed tone all pictures"!

OO-1015: don't log NoSuchFieldException while exporting a group, if the field don't exist, we want that it doesn't exist

OO-716: most charts are horizontal, add units everywhere, refactor to a factory to generate the content of charts for items...

OO-1008 add missing selection ordering to persisted editor instance, remove bogus restricted edit mode

OO-1002: implements 2 more tabs with the list of my lists and shares (pools and groups) to select from

OO-1004: encode softly the webdav names for group and resources to preserve as much as characters as possible

OO-1010: rewrtie the section form to be FlexiFormed, add rich text edition to the section objectives