NEW CR Issue (core): Is [reference parameters] ordered or unordered?

The definition of [reference parameters] in the core says that its type
is "xs:any (0 .. unbounded)".  There is no mention, either in the
notation conventions in section 1.1, or in the description of [reference
parameters] itself in section 2.1, of whether this means a /list/ of 0
or more xs:any (order is significant and duplicates are OK) or a /set/
(order is not significant and duplicates are ignored).

On the one hand, the text in 1.1 suggests that order is not important,
since it only mentions cardinality.  On the other hand, [reference
parameters] are to be represented as an XML infoset, which implies
order.  Given that [reference parameters] will ultimately be seen as
SOAP headers, which are unordered, we should specifically say that
[reference parameters] are unordered.

Similar considerations apply to [metadata], but it is not clear whether
metadata should be considered ordered or unordered.