Major update. Changes to StartMenu, OptionsPage, HelpPage, GameLoop, new Application class, new global (GL) attributes in globals.py, new EXIT_GAME function.  (1)-Added new class, Application, an instance of which is created and then called instead of StartMenu; this class holds an outer while loop for the application.  (2)-Application creates a single instance of StartMenu, OptionsPage, and HelpPage; entering one of these pages simply calls the appropriate already-created instance of the page. That is, only one instance of each of these classes is created while the game is run (which improves over previous logic).  (3)-In contrast to these Page classes, no instance of GameLoop is saved within Application to be subsequently accessed.  Instead, every time a new game starts, a new instance of GameLoop is created and subsequently called.  (4)-Several self attributes of GameLoop are now objects at the module level of globals.py which is imported as GL (i.e. import globals as GL).  Specifically, self.screen -> GL.SCREEN, self.clock -> GL.CLOCK, self.fps -> GL.FPS.  Note: self.surface was removed as it was equivalent to self.screen, which is now replaced by GL.SCREEN.  (5)-Some setup code at top of main.py moved to globals.py.  (6)-Some setup code within GameLoop.__init__ moved to globals.py.  (7)-New NEXT_PAGE attribute in globals.py, access as GL.NEXT_PAGE.  (8)-New EXIT_GAME function in globals.py.