Add signed-request, plus signed GET, POST, PUT, and DELETE convenience
wrappers that generate OAuth parameters, Authorization headers, and execute
through clj-http.
The signature base string now applies RFC 5849 URI normalization (lowercase
scheme and host, drop the default port, exclude the query and fragment), so
requests with a query string, a default port, or a mixed-case host sign
correctly.
verify no longer double-encodes the token secret.
form-decode splits each pair on the first = only, so padded base64 token
secrets are no longer truncated.