Sqaush view/level queue into one queue

Saw the todo in in code and thought i would fix it. I changed the naming from 'level' to 'layer' mostly because i thought is made it clearer but if you don't think it's appropriate i will revert that. Otherwise nothing much to say, this shouldn't take noticeably more memory as the previous version was boxing the level into a `Integer`. However if memory / allocation time would ever become a problem is't easy to start caching the `LayeredView` objects.