Self-provided test suite and assert @version correctly when specified (port of #179 to 0.5.x)

[aredridel]

This does not get CI working, as the tests (obviously) do not pass yet for this branch. However, it does make it possible to see real status in CI.
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• I published the json-ld.org test suite as an npm module. I'm happy to pass on the keys to that npm package for updates if that is a concern; Also happy to maintain that going forward, I don't anticipate a lot of work there, but won't be making it a priority for my work unless someone wants to poke me about it
• I added code to conform to tp003 and tp006 tests, asserting that version is 1.1 if it is specified at all.

[davidlehn]

@version support added in 0.5.x here:
f6a91c0

[gkellogg]

I think this PR is probably obsolete with the collective changes in https://github.com/digitalbazaar/jsonld.js/tree/0.6.x.