Add test for ensuring list order when round-tripping from RDF

[msporny]

We need a test to ensure that list order is maintained while round-tripping to/from RDF.

[gkellogg]

fromRdf-0004, fromRdf-0005, and fromRdf-0006 uses a list.
toRdf-0013, toRdf-0014, toRdf-0015, toRdf-0025 all test generation of RDF lists from JSON-LD.

This seems adequate

[msporny]

Agreed that it's adequate.