2015-11: - scores of exercises in exam can be downloaded by csv.
         - add also duration of the exam sessions.
         - presentation of the lists of sheets, exams, votes in tabs in the standard theme
         - change some menus in visitor page (not finished).
         - in the intromenu of oef exercises, the exercise which has been selected
   is now at its place (not the first one).
2015-11-13: [r9691] add option wims_scoreexam_withoutip for exam scores without IP checking
2015-11: [r9629] - can generate automatically the sheet associated to a public document
     when it is inserted in a class
         - can copy sheets as exams in one click
         -  automatic update of sequence data when deleting doc, exam, sheet in a sequence
2015-10-14: add script date.pl and slib for manipulation of dates.
2015-10-24: [r9652] fix a bug with dashed lines in flydraw (GK)

2015-10-14: [r9641] Add javascript tabs on sequence page for participants
   (when theme used allows it) (OB)
2015-10-13: [r9626] adds top back button (OB)
2015-10-09: [r9618] mathml zooming on span-element. (JE)
2015-09-30: [r9568] MathML fontsize synchronised with HTML (JE)
2015-09-29: [r9567] add varfilter to skillbullet
2015-09-27: [r9551] add symbols for the activities for participants
  and the corresponding legend.
2015-09-26: [r9540] all the mathcal fonts are now available.
2015-09-26: [r9539] colored square for exercises in home page are now clickable (FG)
2015-09: can clone a class. (FG)