CAL-976 NaN/NaN/NaN is displayed in ToDate field when delete data in FromDate field
CAL-980 Wrong tooltips when drag and drop an event from recurring event
CAL-977 Calendar is blank when change default view to List
SWF-2923 : Create pkg-improv branch and update projects versions

Signed-off-by: Arnaud Héritier <aheritier@exoplatform.com>