Changes to support passthrough of errors from the API. Previously we were providing misleading error codes in a lot of cases
Added a test to make sure these passed through appropriately
Moved the "load_tokens" call out of the initialize method. In the pairing use case, this throws an error, since the client is not yet paired. Refactored the "get_token" method to call load_tokens if the token is not found directly.
Also corrected a minor error in the test formatting that was hardcoding a value instead of using the helper constant