termui - top procs that exit are removed from graph too soon

[mranney]

On the termui "top procs" pane, a top process is only shown as long as it remains in the "top" as defined by the sorting scheme. If it drops out of the top or exits while it's data is still scrolling along, it mysteriously disappears. All of this data is still in memory, but by sharing the per-proc summary list, we run into this problem.