ranges.remove(5,10);
assertEquals(ranges(range(0,5),range(15,20)), ranges.toArrayList());
// overlapping add...
ranges.add(4,12);
assertEquals(ranges(range(0,20)), ranges.toArrayList());
// Removes are idempotent
ranges.remove(5,10);
assertEquals(ranges(range(0,5),range(15,20)), ranges.toArrayList());
ranges.remove(5,10);