Implement the 'literal' or 'quote' subcommands

[mslinn]

The ftp man page describes those subcommands as:

 quote arg1 arg2 ...
                 The arguments specified are sent, verbatim, to the remote FTP server.

The literal subcommand is an alias for quote

Either of these subcommands would be helpful when communicating with a mainframe. Yes, dinosaurs do exist! These commands are used with the IBM ftp server to allow files to be transmitted between dinosaur-era filesystems and *nix-era file systems.

I expect that implementing this command should be relatively straightforward. If implemented, this command would allow me to write a Ruby script that could submit JES2 for executing jobs on a mainframe via FTP. Currently, this requires a manual process.