caseFolding: If TRUE, XML attribute and element names
      will be case-folded.
caseFoldingTo: May be either CASE_UPPER or CASE_LOWER
      and sets the target case for the case-folding.
debug: May be either TRUE or FALSE, thus enabling or
      disabling complete debugging information. May also be an array
      containing the names of elements to which the generated
      debugging information shall be limited. The special keywords
      "&CDATA" and "&RECURSE" may be used to enable debugging
      information for CDATA and recursion events.
recursiveOperation: If TRUE, the transformation will
      continue recursively until the XML contains no more overloaded
      elements. Can be overrided on a per-element basis.
overloadedElements: Associative array with pre-defined
      set of overloaded elements.
overloadedNamespaces: Associative array with pre-defined
      set of overloaded elements.