Story: cells with more than three neighbours die

	As a game producer
	I want cells with more than three neighbours to die
	So that I can show the people with money how we are getting on

	Scenario: blink

		Given the grid looks like
			.....
			...XX
			...XX
			.XX..
			.XX..
		When the next step occurs
		Then the grid should look like
			.....
			...XX
			....X
			.X...
			.XX..
