If events have been saved to iPhone calendar app, DataManager checks during data updates to see if user has removed the event from the calendar using the iPhone calendar app.  If event has been removed, data model is updated accordingly.
Using the _informationDictionaryOfCalendarEventsArray, DataManager checks for date changes for events saved in iPhone calendar app.  _eventTimeChangeOccurred is set to YES if change is found.  No other action is taken.  Event date is not corrected in iPhone calendar app.  User is not notified.