Notes
For libxml2.
DOCTYPE comes out as a tag with the top-level tag name (e.g. dataset in
mtcars.xml)
Can we distinguish it.
Reading raw.xml doesn't work.
XML_ENTITY_DECL in createXMLNode needs to be handled carefully.
test.xml causes problems because of definition of entity referring
to an entity.
> parseDTD("data/foo.dtd")
Error in parseDTD("data/foo.dtd") : error in DTD data/foo.dtd
In libxml1.8.9, the processing instructions in raw.xml are not displayed.
It is in the value section.