bug in JSON LD parsing

[Erich Bremer]

The base URI of a jsonLD file doesn't appear to be swapped out correctly.
The first "./" is replaced correctly with the specified base, but after
that, blank nodes that don't end up in the final graph seem to be created.

See:
https://github.com/ebremer/jenabug

using the following code to read in a JSON-LD file:

        Model m = ModelFactory.createDefaultModel();
        InputStream inputStream = new FileInputStream("demo.jsonld");
        RDFParser.create().base("https://demo.com
").source(inputStream).lang(RDFLanguages.JSONLD).parse(m);
        System.out.println("Number of triples : "+m.size());
        RDFDataMgr.write(System.out, m, Lang.NQUADS);

demo.jsonld:
{
"@context": [
"https://w3id.org/ro/crate/1.0/context";
],
"@graph": [
{
"@id": "blam.ttl",
"@type": "CreativeWork",
"about": {
"@id": "./another/local/3223423423"
}
},
{
"@type": "CreativeWork",
"@id": "ro-crate-metadata.jsonld",
"conformsTo": {
"@id": "https://w3id.org/ro/crate/1.0";
},
"about": {
"@id": "./"
}
}
]
}