top: refactor graph support of cpu/mem summary display <=== port of newlib 2d5b51d1

top: refactor graph support of cpu/mem summary display <=== port of newlib 2d5b51d1

______________________________ original newlib message

The logic (illogic?) in the sum_tics() and do_memory()
functions has grown to become almost unfathomable over
time. Additionally, though perhaps not apparent in the
code, many steps are duplicated within those routines.

So, this patch refactors all the summary graph support
to consolidate duplicated code and (hopefully) make it
more understandable with an eye to future maintenance.

[ additionally, that show_special guy's workload has ]
[ been reduced by eliminating any special directives ]
[ previously embedded in some cpu graphs even though ]
[ a cpu may have been idle during the last interval. ]

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