I would love to have hooked into the pretty inspect features which provide a better format, with indentation and colours for the console. But I couldn't find out how to.
The `dfc-b:hasType` value can only be parsed as object id if the context
contains:
```
"dfc-b:hasType":{
"@type":"@id"
},
```
The standard context includes this and it's easier to use. Now that the
URIs of product types are correctly resolved, we don't need to
substitute the URI manually.
Also dropped an old unneeded spec for backwards compatibility.
