Example data uses property "ccodes" that is not defined in context

[gklyne]

In the README example data, I see:

 "properties":{
    "title": "Abingdon (UK)",
    "ccodes": ["GB"]
  },

But in the context file (linkedplaces-context-v1.jsonld), I can't find "ccodes" defined.

[gklyne]

For now, I'm going with

"ccode": {"@id": "gn:countryCode"},