Fix until date in event recurrence editor

- fixed date picker
- fixed JavaScript error caused by French translation
- fixed until date definition when timezone of active user was different
  from the system timezone
- fixes #2173, fixes #2175
Proper fix for #2163.
Update NEWS file
Fix IE error when automatically loading HTML image
Update datepicker CSS
Fix datepicker arrows for IE7
Fix column display for subfolders of draft & sent
Add missing translation string to UI/Common
Add missing languages in preferences module