NotImplementedError
* oauthlib.oauth2.rfc6749.request_validator.RequestValidator.get_jwt_bearer_token
* oauthlib.oauth2.rfc6749.request_validator.RequestValidator.validate_jwt_bearer_token
* oauthlib.oauth2.rfc6749.request_validator.RequestValidator.get_id_token
* oauthlib.oauth2.rfc6749.request_validator.RequestValidator.validate_id_token
* oauthlib.oauth2.rfc6749.request_validator.RequestValidator.get_authorization_code_scopes

Docs:
* make it clear that setting a class var can be used to extend the validity
	e.g.
    token_expires_in = 2592000  # 60 * 60 * 24 * 30

Coding:
* some of the Py3 support regarding string encodings looks wonky.

	`utils.oauth1_to_pyramid_Response` - should utf-8 be the default?  Does the RFC default to iso-8859-1 ?
	
