Method union

src/main/java/field/utility/Rect.java:33–39

(Rect r, Rect rect)

	}

	public static Rect union(Rect r, Rect rect) {
		if (r == null)
			return rect;
		if (rect == null)
			return r;
		return r.union(rect);
	}

	public static Rect union(Rect r, Vec2 rect) {
		if (r == null)