top: swat a potential buglet affecting new graph modes

This patch will cure a potential aberration associated
with a terminal's size (SIGWINCH) and top's new graphs
modes. The symptoms were a dangling tilde (~) plus the
potential loss of a graph's right-most visual content.

The condition was only apparent when a %Cpu approached
100% usage. Also the apparent loss of content affected
the 'block' graph only. With 'bar' graphs, that affect
became the loss of proper right-most bar graph colors.

The cause was determined to be a combination of: 1) an
unnecessary snprintf precision specification; and 2) a
rounding quirk for any graphs which displayed distinct
types of information (as for user/syst, used/unavail).
These could then combine to produce an extra bar/block
which, in turn, resulted in the truncation of a pseudo
termcap attribute used by the show_special() function.

What was originally interpreted as an intractable race
condition turns out to be just a self inflicted wound.

Reference(s):
http://www.freelists.org/post/procps/top-Possible-bug-in-the-graphs,1

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

top/top.h

@@ -51,6 +51,7 @@
 //#define PRETEND8CPUS            /* pretend we're smp with 8 ticsers (sic)  */
 //#define PRETENDNOCAP            /* use a terminal without essential caps   */
 //#define PRETEND_NUMA            /* pretend 4 (or 3 w/o OFF_NUMASKIP) Nodes */
+//#define QUICK_GRAPHS            /* use fast algorithim, accept +2% distort */
 //#define RCFILE_NOERR            /* rcfile errs silently default, vs. fatal */
 //#define RECALL_FIXED            /* don't reorder saved strings if recalled */
 //#define RMAN_IGNORED            /* don't consider auto right margin glitch */