top: add graphs modes for cpu and memory, program code

top: add graphs modes for cpu and memory, program code

This patch makes 't' (View_STATES) & 'm' (View_MEMORY)
commands into 4-way toggles. The two new modes provide
for two different graphs of the cpu and/or memory use.

These new capabilities are similar to those offered by
the 'htop' program. However they're aesthetically more
pleasing (to me) plus the scalings are more authentic.

Poor ol' top has long been troubled by the comparisons
offered up by the 'htop' program. Many of those things
were only true of the original redhat top while others
are no longer true of this current top program. So let
me use this commit msg to begin to correct the record.

Corrected comparisons between 'htop' & 'top' programs:
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+ htop does not start faster, actually reverse is true
+ top offers scrolling vertically and horizontally too
. (and top offers better <Home> and <End> key support)
+ unassigned keystrokes don't subject top to any delay
. (but htop suffers that annoying ncurses <Esc> delay)
+ in top one need not type the PID to kill the process
+ in top one need not type the PID to renice a process

Some things the 'htop' program was not bragging about:
------------------------------------------------------
+ top can outperform the htop program by a wide margin
+ htop + SIGWINCH = corrupted display + restart likely
+ htop cannot preserve its screen data at suspend/exit
+ the htop column management scheme is very cumbersome
+ htop allows columns to be duplicated again and again
+ htop displays only full command lines, not pgm names
. (and that 'Command' column must always be displayed)
. (and it must always remain as the last column shown)
+ htop does not provide for any sort of command recall
+ htop's search feature does not highlight any matches
+ there is no 'find next' outside of htop search modes
+ htop does not allow Header or Process memory scaling
+ htop provides no flexibility on column justification
+ htop does not provide the means to change col widths
+ htop provides less control over colors configuration
+ htop always overwrites the rcfile with any UI change

Someday, maybe we'll provide a better comparison as an
addendum for (or replacement of) that README.top file.

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