$repeat does not play nice with HTML elements

It is not possible to $repeat a component that has a HTML element as an ancestor.

Example tree:

```

Never!

```

Results in error:
`Uncaught Error: ParentNode with UID`null`does not exist. Unable to process $if/$repeat`

---

Similarly, it is not possible to `$repeat` a HTML element.

```
behaviors: {
'.item': {
'$repeat': '[[identity|products]]'
}
},
states: {
products: [1,2,3,4]
},
tree: `