Method connect

src/main/java/fieldbox/boxes/Box.java:121–137

Connect box 'b' to this box. b is now a child of this box, this box is now a parent of 'b'

(Box b)

	/**
	 * Connect box 'b' to this box. b is now a child of this box, this box is now a parent of 'b'
	 */
	public Box connect(Box b) {
		if (children.add(b)) all.addLast(b);
		else {
			// restore ordering to LinkedHashSet
			children.remove(b);
			children.add(b);
		}

		if (b.parents.add(this)) b.all.addFirst(this);
		else {
			// restore ordering to LinkedHashSet
			b.parents.remove(this);
			b.parents.add(this);
		}

		return this;
	}