Adding a new property to the KotlinInvaersView class shown with some context to make it clear where it goes

KotlinInvadersView.kt

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// A Canvas and a Paint object
private var canvas: Canvas = Canvas()
private val paint: Paint = Paint()

// The players ship
private var playerShip: PlayerShip = PlayerShip(context, size.x, size.y)

// The score
private var score = 0
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