XML pull parser dependency includes javax.xml.namespace.QName.class

This is a problem on enterprise containers such as Weblogic where if we want the container to prefer web application provided classes this leads to LinkageErrors.

There is an alternative mini jar provided by xpp3 that doesn't ship with the QName class. However this needs some code changes and removal of an indirection level.

JCRDiff also pulls in xpp3 dependency, but this is unnecessary and must be fixed.