With reference to https://github.com/idan/oauthlib/issues/182 we should keep track of the upcoming changes in oauthlib regarding refresh token grant. In particolar, `confirm_scopes` method in `RequestValidator` does not longer exist and we should implement `get_original_scopes` instead. The change has to be ready when we will upgrade the supported oauthlib version. For the moment I set the milestone for this issue at 0.4.0