Code to make RDF ontology from CSS properties JSON

[timbl]

No description provided.

[tidoust]

Thanks. The code seems good but I'm not fully clear what value such an RDF ontology is going to bring if:

1. It only contains CSS properties from the CSS 2.2 specification (../ed/css/CSS.json), excluding CSS properties defined in other CSS module specs (the other JSON files in ../ed/css/). What are usage scenarios that only need CSS 2.2 properties?
2. Its maintenance is not automated. In other words, https://www.w3.org/ns/css.ttl strikes me as a brittle source of truth if it gets updated manually. Automated maintenance is doable. I note we need to fix/improve a couple of things first (starting with making sure that CSS properties are defined only once, see CSS package: consider additional parsing guarantees #127)

[tidoust]

Suggested change

	The same camelcase convention is usede as is used by the subproperties of the
	The same camelcase convention is used as is used by the subproperties of the

[tidoust]

I note that the JSON file exposes the camelcase name in the styleDeclaration property (last item in that array), so the camelCase function could be dropped and this line replaced by something like:

Suggested change

	const camel = camelCasify(prop)
	const camel = cssData.properties[prop].styleDeclaration.pop()

[tidoust]

Going ahead and merging the PR. I filed #366 to track improvements and automation.
I'll add the editorial fixes after merge.