cli: Consistent box name parameter name (BOX_NAME) in task descriptions.
Pulled --debug class_option up to parent class.
cli: Add class_option --cwd to change the working directory.
cli: Moved provider independent templates and list task to parent class.
cli: Make provider name and usage available to class and instance.
cli: Moved common task methods into parent class
     (destroy, halt, up, ssh, winrm, copy, define, undefined, ostypes, sendkeys)