RDF/A version 3

This version implements RDF/A, and fixes a white space bug in XMLLiterals.

(Note: need to pass through an RDF/XML parser to get the triples, e,g. 
RDF Validator on W3CC site. I have also just had a bug report on the 
treatment of the default namespace in ARP, i.e. the W3C Validator, in 
XMLLiterals, which may be dropped in error)

I attach a copy of the RDF/A document that it implements

Jeremy