feat(tokens): change to json for token format
feat(token): add a dict interface to Token
fix(token): Token() does not have a value parameter anymore
feat(token): Token() accepts a dict
feat(token): do not add a timezone to the token
fix(token-client): encode tokens as real objects when validating them
fix(token-client): encode tokens as real objects when transforming them
fix(token): fix __hash__ and __eq__ for Token
feat(token): partial token support
fox(token): only accept either hash or token
test(token-authority): check that it accepts partial tokens