The additions made with this commit are as follows:
-Added a ListDataListener class in a new package called Refresh.
 the name of that class is RefreshListenerUponEventCreation, and
 it is used at this point in time in order to update the CalendarSidebar
 when a new event is created in the EventEditor class.
-Modified the GlobalButtonVars class in order to update the events displayed
 in the CalendarSidebar when the view state is changed between any of the
 three view states of personal, team, and both.
-Updated the ToolBarView class in order to facilitate the changes that were
 made in the GlobalButtonVars class.
-Created getInstance() methods for the GlobalButtonVars and CalendarSidebar
 classes.

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STILL IN PROGRESS AND NOT PROVIDED WITH THIS COMMIT
-Automatic refreshing after first drawing from the server to populate the
 local EventModel.
-Appropriate commenting (will be provided tomorrow).
-getInstance() methods for the GUI components of DayView, WeekView, MonthView,
 and YearView.
-Automatic refreshing upon entering a different tab view (Day, Week, Month, or
 Year).
-Automatic refreshing for the GUI components of DayView, WeekView, MonthView,
 and YearView upon a change in view state (personal, team, or both).
Addition of RefreshListenerUponEventCreation class.
Merge conflict resolution in EventEditor and CalendarSidebar classes.