Added one more comment to the GameplayView.java class. This is to test
how branches are allowed to be different from the master, and how that
is changed on the GitHub website.
[1] OnGameOverListener and OnMarkerPlacedListener consolidated with
	GameStateListener.
[2] Changed how the constructors of the Marker class work. They no
	longer call Player.setMarker when given a Player as an argument.