StartMenu: 1) couldn't figure out how to enlarge the text of the JLabel
in the titlePanel, 2) had trouble resizing buttons; 
GameplaySettingsMenu: 1) maybe add labels for the various subpanels, 
2) chose a purpose for the fillerPanel (concept art?), 3) when clicking
the Start button in the StartMenu GUI, it correctly opened the
GameplaySettingsMenu GUI; and when I exited the GameplaySettingsMenu
GUI, the old StartMenu GUI didn't require closing (so, maybe it's not
necessary to explicitly close the StartMenu GUI when the
GameplaySettingsMenu is created...?!). -Reid