PermissionGroup now uses Events (from JavaLibrary) rather than rolling its own observer pattern.
Added PermissionGroup.getPermissionStatuses()
Added overrides for .equals(...), .hashCode(), and .toString() to PermissionStatus
Added methods to PermissionsRegistry dealing with multiple permissions/groups in a single operation.
Made PermissionsRegistry's required fields accessible. (Though still not writable)
Created PermissionsRegistryDecorator, and turned ThreadsafePermissionsRegistry and PermissionsRegistryWithEvents into decorators.
Added the capacity to MissingPermissionException (and its subclasses) to properly represent multiple permissions missing.
Added more testing for PermissionsRegistry and its subclasses.