Return an array that matches the XML parsed. This code is lifted from
Stephan Schmidt's XML_Unserializer
class in the XML_Serializer package. As such, tags are represented by an associative
array. Multiple tags are represented with a 0-based array of tag contents, and
attributes are represented by an array index named
If attributes are present, the array index
_contents is used to
hold the contents of the xml tag.
throws no exceptions thrown
This function can not be called statically.