Redirect completion to sub-process

[frankcarey]

It would be awesome if bash-completion could be redirected down into the subprocess.

Example command:

commands:
  complete:
    cmd: git

When I type ahoy complete <TAB>, I get nothing (process hangs because the current setup is actually calling the 'git' command instead of forwarding the to it.

Related issue about causing commands to actually run! urfave/cli#272

It looks like we might be able to simulate keypresses using echo -e "\t" | git
See : http://stackoverflow.com/questions/6264596/simulating-enter-keypress-in-bash-script