Latest draft ready for review before making voting versions

I've made the following changes in the hub document from CSD4D1 to CSD4D2:

 - removed reference to "latest version authoritative XML" because of an
   OASIS server issue with server-side redirects
 - Annex A.3 - made reference to distribution directory in which to find ZIP
 - Annex A.3 - removed reference to ASN.1 directory in the distribution
 - Annex C.7 - made reference to only document ABIEs having UML diagrams
 - Annex G   - changed introductory text
 - Annex G.1 - changed reference to ASN.1 resources to point to repository
 - Annex G.2 - added section for complete set of UML diagrams in repository