huey: Internal maintenance specification

This class is a compound widget containing all the general controls for the program:

Because this widget is designed to take up a fairly thin slice across the top of the application, these controls are gridded in a horizontal row. The class inherits from Tkinter's Frame class, so it is effectively a compound widget—just a big widget with other widgets inside.

# - - - - -   c l a s s   M e n u B a r

class MenuBar(Frame):
    """Compound widget containing general program controls.

      Contained widgets:
        .__helpButton:  [ a Menubutton that displays help text ]
        .__quitButton:  [ a Button that terminates the application ]

      Grid plan:
          0               1
         +---------------+---------------+
       0 | .__helpButton | .__quitButton |
         +---------------+---------------+
    """