use class hierarchy, raise props to appropriate level

[VladimirAlexiev]

While posting #26 I noticed the more general problem:

• http://schema.org/Thing has common props applicable to most things, including name description url
• gs1 doesn't seem to use such practice
• instead, many props have the same meaning but per-domain URL.
  • Eg there's organizationName but no countryName #23?
  • There's additionalProductClassificationCodeDescription but no organizationDescription?
  • IMHO a name is a name, and a description is a description, no matter what it is applied to. Why use different props?
• Why not adopt this practice? It's the basic inheritance mechanism that simplifies the ontology, allows reuse of prop characteristics and definitions, facilitates "fair treatment" of common props across classes, saves time
  • also facilitates consistency and correctness of definitions (eg #26 shows a bad definition relative to the very narrow domain of that prop)
• The ontology browser should show "inherited props" like schema.org does