Failing test: Item's properties can't be changed. Throws metamorph exception

Hi,

If a property of an item is changed after it's DOM has been reused at least once, the following error is thrown:

```
Cannot perform operations on a Metamorph that is not in the DOM.
```

It seems to be because of the way the item view's `innerHTML` is changed in `_contextDidChange`. It worked until c20a2e7588234b8c4b9de29c5db4cfe6739fcc3a.

Any good ideas?