Requirement: Mark areas where a ship has been hit

[shtwzrd]

User story

As a Player,
I would like to be able to see where my shots have hit the enemy,
so that I can keep track of the enemy ships my fleet has hit.

	Acceptance test
Prerequisites	Player has fired at least one shot that was a hit and one shot that was a miss
Expected Input	A game state in which the above prerequisite is met
Expected Output	The square that was hit and the square that was a miss are visually distinguishable