CSC301: Tree code: Make right call independent of the left [43/56]

    public int size () {
        return size (root, 0);
    }
    private static int size (Node x, int sz) {
        if (x == null) return sz;
        sz = size (x.left, 0);
        sz += size (x.right, 0);
        sz += 1;
        return sz;
    }

Make it so that the right does not know about the left!

Change so that size returns just the size of x, rather than size of x plus sz

Intial value of sz is always 0