code: def setTimeStart( self, timeStart ):
          
          timeStart = QTime(timeStart)
          
          length = self.length() # in minutes
          self._timeStart = timeStart
          self._timeEnd   = timeStart.addSecs(length * 60)
          self.markForRebuild()
docs: Sets the start time for this item.  This will automatically push the
          end time to match the length for this item.  So if the item starts
          at 11a and ends on 1p, and the start time is changed to 12p
          the end time will change to 2p.  To affect the length of the 
          item, use either setLength, or setTimeEnd.
          
          :param      timeStart | <QDate>