o Add a check command that runs and can check to see if the previous
  command failed.

o Add a 'backout' command.  If the command fails, then it will execute
  the backout commands (in reverse order) to back out the changes.  An
  optin exists to say whether the backout command will execute if THIS
  command fails, or only if future commands fail.

o ???: In ssh, add a list of pre-commands that are run on the local host before
  ssh is started up (such as initializing an ssh-key).
