New instantiates a ready-to-use Cli.

Subcmd is a subcommand of the main "docker" command.

Cli represents a command line interface.

ClientFlags represents flags for the docker client.

CommonFlags represents flags that are common to both the client and the daemon.

An StatusError reports an unsuccessful exit by a command.

Handler holds the different commands Cli will call It should have methods with names starting with `Cmd` like: func (h myHandler) CmdFoo(args ...string) error.

Initializer can be optionally implemented by a Handler to initialize before each call to one of its commands.