New Class: TrainGraphics. Creates a Panel that extends JPanel showing
an index label for the carriage number on the train, the carriage image,
and the carriage.ToString label. This allows us to be able to change the
values in the labels when necessary. 

Have shunt train working and appears to be bug free. Although we need to
fix the disabled and enabled buttons to disallow a user from shunting
while a train is shunted.