bumped up release version
further clean-up of schema
better data linking + some RDF serialization fixes (in regards to the source URL)
clean-up: small refactoring of serialization so that is is little simpler
ICO now serialized as 'adms:Identifier' (and 'rov:RegisteredOrganization' links to it)
clean-up: further refactoring of serialization to make it simpler: getConceptRdfAbout() removed
RDF output optimization/clean-up: do not put NS definitions where they are not used