top: add variable width data display without scrolling

top: add variable width data display without scrolling

There are times when one might want to see some task's
particular variable width data. However, prior to this
commit, the only way was to first turn on a field then
scroll through it via repeated right arrow keystrokes.

[ this also required that field to be displayed last ]

Needless to say, given the potential length of some of
that variable data this could be extremely cumbersome.

Now with this patch, a Ctrl keystroke combination will
create a separate window at the bottom of the terminal
screen where such variable width data is seen in full.

[ the targeted task is the 1st task displayed, which ]
[ is a convention employed in some existing commands ]

[ the targeted data was determined by these Ctrl key ]
[ combinations: CtrlG = ctrl group; CtrlK = cmdline; ]
[ CtrlU = supplementary groups; plus CtrlV = environ ]

Signed-off-by: Jim Warner <james.warner@comcast.net>