NEW ISSUE: Comparison of URIs used as identifiers.

Several of the URIs defined by WS-Addressing are used primarily for
identification rather than primarily dereferencing: [message id],
[relationship], and [action].  In other specifications, how to compare
values of these properties is usually defined.  WS-Addressing would
benefit from a section like this as well.

I propose we essentially copy the WSDL 2.0 section on this into the WS-A
spec:
http://dev.w3.org/cvsweb/~checkout~/2002/ws/desc/wsdl20/wsdl20.html?cont
ent-type=text/html;%20charset=utf-8#uricompare