General
-added all missing @Override annotations
-normalized lines to 80 characters per line
-removed unused imports
-changed some hardcoded numbers into constant variables
-added res/audio/sfx and res/audio/music folders

Art.java
-fixed typo "Loading art files after already art has already been loaded"

BlackbeardsRedemption.java
-changed state variables (list of static final ints) to enum
-added two new states, CREDITS and SETTINGS

BbrGameState.java
-removed unnecessary SlickException throw from constructor

Button.java
-fixed issue causing autoResize() to be called twice
-condensed autoResize() (1 line) and changeSize() (3 lines) functions into setImage()
-added checks so that draw() will not crash if the image is null (previous behavior: access null pointer)
-changed checkClick() to always return false for a null image (previous behavior: access null pointer)
-buttonShape renamed to bounds for clarity and is now only initialized if image is not null (previous behavior: access null pointer)
-bounds are not initialized until the image is first drawn (previous behavior: button can be clicked on before it is drawn to screen)

MainMenuState.java
-Added placeholder start button
-Added placeholder menu music that fades out when game is started