Renaming work in ONMjs.Model, new methods on ONMjs.Address...

... Some reworks in ONMjs.Model to clean up the naming conventions used for "namespaceDescriptors" (i.e. the processed form of a namespace data model declaration (using terms from the ONMjs documentation).

Additional methods added to ONMjs.Address class: getNamespaceDeclaration (returns a reference to the raw namespace data model declaration), and getNamespacePropertiesDeclaration (returns a reference to the namespaceProperties subnamespace of a namespace data model declaration).

Corollary changes in observers...