Added base scp file.

See also http://www.hypexr.org/linux_scp_help.php.

Also, I was going to add files for commands like `mv` and `cp`, but then I remembered part of the project description: "It was designed to help remind *nix system administrators of options for commands that they use frequently, but not frequently enough to remember." `mv` and `cp` are pretty elementary commands, so I suppose they don't fit that description. However, if you think adding them wouldn't do any harm or would be beneficial, I could do so.