schema/spec-wd-02

This is still messy - I'll make a better version later in the week, but any 
comments are appreciated.

Changes:
  - Data -> XMLData and Base64Data
  - "auto-enveloping" of Input Documents based on RefType removed from 
Basic Processing - if the client wants an enveloping signature, he can 
splice the documents into the returned signature himself.  We can add 
Options for server-performed enveloping/enveloped signatures.
  - Added a skeleton for Verify Request/Response
  - Added a <dss:Signature> to encapsulate signatures in SignResponse and 
VerifyRequest.  These can contain:
    - <ds:Signature>
    - <dss:Base64Signature> with a MimeType - e.g., 
application/pkcs7-signature or application/pgp-signature.
    - <xs:any> for extensibility
    - <dss:SignaturePtr> - this uses an xs:IDREF and XPath expression to 
point to a signature in an <InputDocument> (in a VerifyRequest message), or 
perhaps in an Option in a SignReponse message (example: This isn't spec'd 
yet, but the client could request a server-performed Enveloped 
Signature.  The server returns the enveloping document as an Output.  Since 
it would be redundant for the server to also return the <ds:Signature> 
separately, he'll just return a <dss:SignaturePtr> to the signature inside 
the enveloped document.)
  - Added a <ds:Status> for use in <SignResponse> and 
<VerifyResponse>.  This is patterned after SAML's status element, but 
simpler - SAML has 2 layers of status codes, and an additional 
<StatusDetails> for returning additional parameters.  The statuscodes need 
to be fleshed out - is this the right approach, though?
  - Moved editorial issues to section 5.  We have 2 outstanding issues.

http://www.oasis-open.org/apps/org/workgroup/dss/download.php/3821/oasis-dss-1.0-core-schema-wd-02.xsd
http://www.oasis-open.org/apps/org/workgroup/dss/download.php/3823/oasis-dss-1.0-core-spec-wd-02.doc
http://www.oasis-open.org/apps/org/workgroup/dss/download.php/3822/oasis-dss-1.0-core-spec-wd-02.pdf

Trevor