Description
Addressed comments raised by reviewers...
Corrected the namespace and description of TopicSpaceLocation attribute (WSN 4.21)
Corrected schemaLocations in the TopicNamespace and TopicSet examples (AI 138)
Reworded the definition of wstop:Topic/@parent, and reworded bullet 3 of 6.1 (WSN 4.4)
Revised words at the start of section 7, to make them clearer (WSN 4.2)