Page property and parameter don't have namespace

The `|?$page` property and the the `{{{Page|}}}` parameter show the page name without namespace. 
This is not correct, since they won't refer to a page if the page is not in the Main namespace. Or if it also exists in the Main namespace, it will refer to the wrong page.

The {{{Page|}}} parameter is passed to the template when using `#display=template`.
@marijnvanwezel 