OO-2732, OO-2784: add selenium test for the drag and drop variety of match interaction, update tests after OO-2784

OO-2756	: add progress bar and percent value for score, add section summary for the questions correct, answered, and not answered

no-jira: selenium tests for QTI 2.1 editor, 2 matches with different settings, scoring and with feedbacks

no-jira: selenium tests for QTI 2.1 editor, 2 multiple choices with different settings, scoring and feedbacks

no-jira: selenium tests for QTI 2.1 editor, 2 single choices wth different settings, scoring and feedbacks

OO-2676: simplify html code of calendar event editor and repository info editor, replace synchronized in velocity with a ConcurentHashSet to reduce lock contention, remove double update method for groups...