UPDATED all class changed, replaced by a new version
CREATED class Window.java 

which is the JFrame of the graphical interface
UPDATED all old class
CREATED class MainJPanel.java

which is the container where the ball and the map are displayed
ADDED picture ball.jpg
ADDED jar executable RollingBallGame.jar
UPDATED all classes package set up to date
MOVED ball.jpg
MOVED picture ball.jpg
MOVED code of the class Window.java into GraphicalDisplay.java
UPDATED classes ConsoleDisplay.java, Display.java,
GraphicalDisplay.java, RollingBallGame.java

REMOVED all things which were referencing the class Window
UPDATED all classes javadoc updated
MOVED instantiation of the ball to Main.java
UPDATED Main.java

now use the instantiation of GraphicalDisplay.java
UPDATED MainJPanel.java
UPDATED GraphicalDisplay.java