FR: support 'monitor' command

[tomquas]

Is your feature request related to a problem? Please describe.
when debugging redis interactions, it's of tremendous help to start a separate terminal session with

$ redis-cli monitor

and trace commands. i'd love to see this support in tile38, too.

Describe the solution you'd like
$ tile38-clie monitor

Describe alternatives you've considered
app logging - too much additional, repetitive effort

Additional context
[none]

[tomquas]

wow, i'm impressed. thank you.

[tidwall]

You're welcome.

[larsw]

Excellent, but noticed that "MONITOR" is not available when doing tab completion in tile38-cli.