Minor cleanup
Major refactor of BaseCommand, BaseRequest
Split BaseRequest.main into preprocess and postprocess
Drop the metaclass, capitalize Args and Filters
Rename Version -> VERSION
Rename APIVersion -> API_VERSION
Rename Description -> DESCRIPTION
Rename DefaultRoute -> DEFAULT_ROUTE
Rename ConfigFiles -> CONFIG_FILES
Rename ServiceClass -> SERVICE_CLASS
Rename Action -> ACTION
Rename ListDelims -> LIST_MARKERS
Rename Name -> NAME
Rename MaxRetries -> MAX_RETRIES
Rename AuthClass -> AUTH_CLASS
Rename EnvURL -> ENV_URL
Nuke do_cli (use run() on the class instead)
Silence pylint's complaints about mro()