Proposal for multi requests

All (and Hal in particular),

I made a schema proposal for the new multiple request scheme. I changed 
it a bit from what Hal posted originally. I change DecisionList into 
MultiRequests since it's a list of requests, not a list of decisions. I 
did use xml:id as Hal suggested.

If I understand xml:id correctly, we do not need to (are not allowed 
to?) declare them in our schema, so I have not changed the schema for 
the <Attributes> element. If anyone is an expert on xml:id, let me know 
of any errors I may have made. It is also recommended by the W3C here 
http://www.w3.org/TR/2005/REC-xml-id-20050909/ that attributes name 
xml:id are used for making references in XML documents. So I did not 
declare our own XML attribute for it.

Best regards,
Erik