idea: output node status after --off / --on

[chu11]

(this ties in with #78)

especially useful with large node counts

$ pm --off foo[1-100]
<wait 60 seconds>
on: ...
off: ...
busy: ...
unknown: ...

the main reason is it can give user an idea of why something didn't work fast / at all. i.e. if you see "busy" a lot, maybe you need to increase timeout.

Edit:

side ideas from @adambertsch, only output with things go bad? also --quiet option

[garlick]

I think this would also be unnecessary if we resolved

• powerman: return textual error on on/off fail #76
• idea: output progress indicator waiting for command to complete #77

[garlick]

I think #76 is probably where we should invest this effort. Closing. Reopen if that makes you sad.