move required attributes spec into initialize, since it is part of that
omit nonce and timestamp by default when using plaintext
simplify things a bit where timestamp and nonce have had to be overridden for consistency, now that they default to exclusion with plaintext.
private key helper in signable request test
signable request test - describe signature
signable request test - exclude given attributes from example attributes (they get merged but symbol/string discrepancies mean I should exclude)
signable request test protocol params
signable request test signed protocol params
signable request test - #example_signed_request helper for requests with an existing authorization
many tests for normalized request params