Document expected behavior when output of load command is redirected or piped

[tleonhardt]

Given the way that the load command for running simple ASCII-text scripts is implemented, redirecting or piping the output of this command has no effect since each command within this script is appended to an internal command-queue, then the load command finishes and cmd2 resumes its REPL loop and begins running the commands in the queue.

We either need to sufficiently document that this is expected behavior or to make redirection and piping work in this situation.

[tleonhardt]

I think load works properly since with a redirect/pipe you are capturing the output of the load command itself, not what it adds to the queue.

Perhaps we should stop referring to load as a script command. It actually loads commands from a script file into a queue and then the normal cmd2 REPL resumes control and executes the commands in the queue in FIFO order.