Changes for Zthes profile, version 0.4

Changes between versions 0.3b: and 0.4

• Change the access point used for all elements searching in accordance with the re-ordering of attributes in the final Utility Attribute Set document.
• Change the function qualifier strings used for searching in accordance with those specified in the final Utility Attribute Set document.
• Update reference to the Utility Attribute Set.
• Add an OID for the AuthorityFileInfo External.
• Add a paragraph noting that the abstract model need have no impact on local data representation.
• Add description of the UNIverse project to Appendix D.
• Add more detail to the description of the Natural History Museum's use of Zthes to Appendix D.
• Minor editorial changes and corrections.