Fix `AttributeTypeView::render()` `$this`

`$this` is used in Attribute elements. This is set from
`Loader::element()`. With the `static` declaration and things like HVVM
`$this` is `null`.

Add additional methods in order to scope and include header and
footer elements

- `AttributeTypeView::includeHeader()`
- `AttributeTypeView::includeFooter()`