Remove duplicate method
Simplify getElementText() - employ Element.getTextContent()
Drop unnecessary Document parameter where Element parameter also given

Use Element.getOwnerDocument() to get the necessary reference to the
Document instance.  It is unnecessary to pass the Document additionally
explicitly as it is illegal to add nodes created from one Document into
another.  For the later purpose one need to use Document.importNode().
Don't encode source text to bytes and have the parser decode it back
Merge pull request #462 from stanio/master

Small XmlUtil simplifications and related cleanup