Scala 2.10 namespace prefix fixes

The xml: prefix should be implicitly allowed (see http://www.w3.org/XML/1998/namespace), but right now, the code will throw this exception:
Attribute with name 'lang' with prefix 'xml' is not defined on element

If an XML Namespace prefix is declared for an existing namespace URI, the code will just ignore it. This causes a similar exception to be raised because of the missing prefix.

Note: use ?w=1 in the GitHub URL to ignore whitespace, since my IDE automatically erased all the trailing whitespaces.