fix minor typo in javadoc
add new API method SesameManager.getOntologyVersion() to work with
both schema/artifact ontologies by refactoring getSchemaVersion()
clean up exceptions thrown
add utility method stringToOntologyID()
modify test to retrieve and validate InferredOWLOntologyID after upload
modify AbstractResourceImplTest.loadTestArtifact() to return an
InferredOWLOntologyID instead of artifact URI only
add version IRI as a required parameter for editArtifactToRdf()
add version IRI to method signature of ArtifactManager.updateArtifact()
test updateArtifact() fails when update is NOT based on the current
version of the artifact.