removed dependency on commons.lang
fixed expires_at property, hid helper functions
unit tests for basic data classes
Fix a bug where a client is deleted before details looked up. Also return 204 on success
Added two unit tests using the Mockito framework
Added comments to unit tests
changed expires_at -> client_secret_expires_at, issued_at -> client_id_issued_at
added tests for ClientDetailsEntity and RegisteredClient data objects
tests for embedded JOSE objects
commentary!