[Serialization] IBM-SE-015: Serializing QNames

It is worth noting that the serialization process depends on the ability 
to cast a QName into a string (for example, when it is found in the value 
of an attribute such as xsi:type="xs:decimal"). Casting a QName into a 
string is currently not defined in the Functions and Operators document. 
This inconsistency between documents should be fixed.

--Don Chamberlin