Update route.js

Modify router.put to support deeper "levels" 
was having trouble with 

```javascript

while (o && pos.length - 1) {
  o = o[pos.shift()]
}

```

binding to an $id

Example:
Using the example from the readme, posting to

http://localhost:3000/rest/blogpost/$id/comments/ 
will work fine, however if you add another level like

http://localhost:3000/rest/blogpost/$id/comments/$id/notes/

I modified the code to assume that any additional layers would follow a path of

/level1/$id/level2/$id/level3/...etc