0.5: move to client credentials grant style OAuth flow.

[pirogoeth]

From the way RFC 6749 reads, client credentials style grant is similar to resource owner password credentials grant, but provides more flexibility.

With the client credentials grant, the main differences are the lack of username and password in the authentication request, as they are provided as HTTP BASIC auth in the Authorization header.

POST /token HTTP/1.1
Host: auth.example.org
Authorization: Basic <base64-mime encoded payload>
Content-Type: application/x-www-form-urlencoded

grant_type=client_credentials&scope=space separated scopes

In the case of pyled, authentication and authorization are taken care of in one step, so this request hits a single endpoint and is essentially finished. As for other OAuth systems, I am not sure.