Action Item: RDFS ontology for interface

Hi all,

Attached is the result of our first effort to create an ontology for
the interface modelReference.

Here is a high level description of the ontology. The primary class is
ServiceProvider, which has three properties:

1) Industry: Used to specify NAICS code and industry sector.
2) Location: Used to specify UN/LOCODE code and location name.
3) Product: Used to specify UNSPSC used to specify product (service) code
    and product (service) type.

We currently envision interface level modelReferences pointing to
instances of ServiceProvider. Comments and suggestions are welcome.

Thanks,
Kunal and John