Non-DOM-contained interpolated values while iterating Observe.Lists

When rendering template views, a DOM error would be thrown when trying to interpolate values within a list if the list's children weren't encapsulated in a DOM node as mentioned in issue #153. This failed with both EJS and Mustache.

This works:
```mustache
{{ #todos }}<span>{{ name }}</span>{{ /todos }}
```

This wasn't working previously:
```mustache
{{ #todos }}{{ name }}{{ /todos }}
```