Release notes updated in preparation for 0.12 release.
Added tawny.owl to symbols. Used in most ontologies!
Ontologies with no IRI now include the name after the random UUID.
Second arity version of ontology-to-namespace.
Fixtures refactored. Now uses dynamic binding, because namespace is
unreliable (tests run in 'user not the test namespace).
New issue with isuperclasses and ilk.