Make sure to traverse children of endContainer when endOffset > 0

The children of an endContainer were not being traversed in certain cases.

consider the markup:

````html
<b>lorem <i>ipsum</i></b>
```

with a range specified as:

```javascript
var range = new Y.Range();
range.startNode(Y.one('b'));
range.endNode(Y.one('b'), 2);
```
traversing the range would result in:
```
<b>
#text lorem
<i> 
```
the text node `ipsum` would never get traversed, even though the offset points to the 2nd child of `<b>`; the `<i>` element.

I think *technically* this is the correct behavior, but it doesn't feel right.  I think the expected behavior would be to traverse the children of the node the endOffset points to