Part of feature request 3521362
Posts can be viewed as XML (or HTML). However exports can only currently be in HTML.
1) Allow exports to be XML or HTML (or both ?)
2a) Allow attached files to be optionally included (this is currently an option to view as XML, but not in exports).
2b) This will result in broken links in the HTML export, thumbnails should always be included for HTML, and file links should refer back to the online version if the files are not chosen to be attched.