top: add '!' toggle for combined cpus display, program
When implementing that earlier '4' toggle, in response
to the issue referenced below, I got to thinking about
those environments with massively parallel processors.
Such environments may not benefit from the '4' toggle.
So, I decided to implement a feature that could enable
use of those '1' and/or '4' toggles no matter how many
active processors top may have ultimately encountered.
With the new '!' toggle, adjacent cpus can be combined
to any degree, represented as a single cpu group/line.