Two new extension functions
are provided. The first argument is a bas64Binary value or hexBinary value, the second is the name of a character
encoding. The function takes the sequence of octets encoded by the base64 or hex binary value, and treats
it as a character string that has been encoded using the specified encoding. It then returns the result of
decoding the value, as a string.
(The function base64Binary-to-string() was found useful in converting LDAP data to XML, and hexBinary-to-String()
was added for symmetry).