[cddlm] more on namespace resolution

[Steve Loughran]

OK, I have one more test that is unhappy with the quirks of namespaces, 
and don't know the implications of.

it is essentially: "how does targetNamespace interact with default 
namespaces of things".

If I have a CDL file which declares a target namespace, are all 
components installed into that namespace
for reference by other things, including the components themselves?

that is: does this document resolve the extension properly, or does it 
fail with an unknown element error:

<?xml version="1.0"?>
<cdl:cdl 
xmlns:cdl="http://www.gridforum.org/namespaces/2005/02/cddlm/CDL-1.0"
     targetNamespace="nap://velvet+underground/european+sun"
     xmlns:tns="nap://velvet+underground/european+sun">

   <cdl:system>
     <Component />
     <Extension cdl:extends="tns:Component"/>
   </cdl:system>
</cdl:cdl>

-steve

ps. the nap: url schema was a relic of napster; each one searched for 
content under that name. I use it for unique names, but also to verify 
that whatever holds the URIs is not enforcing them to be resolvable URLs.