Hi,

Here's a couple of minor changes for ox-html.

First, I dropped the references to HTML5 hgroup since apparently W3
did the same¹.

Second, for some reason ox-html replaces a couple of entities by
itself—rather than letting org-entities do it—but uses hex references
(or whatever), rather than a "nice" HTML character entity.  The second
patch fixes this.  (I naively assume that there is not a reason for
not using the pretty references).

—Rasmus

Footnotes: 
¹   e.g. http://html5doctor.com/the-hgroup-element/

-- 
May the Force be with you