plain JSON test vectors still needed

[bumblefudge]

as noted in #7

[bumblefudge]

@zachferland volunteered on todays call and I will figure out github permissions after the fact

[clehner]

Discussed on call today (#29); unsure if should keep @context in JSON DID document, or use same document as-is (i.e. have single set of test vectors, and maybe update specification to say they can be used as JSON or JSON-LD); not enough context to decide currently.