top: make command line switch parsing even more robust

top: make command line switch parsing even more robust

This program has always tried to maintain an extermely
robust command line parsing procedure, far more robust
that what's available with the getopt stuff. But, with
the introduction of our first numeric switch it should
have been made even more robust than, in fact, it was.

This commit will now accomplish such a desirable goal.

Reference(s):
. added '1' command line switch
commit 89db82d143d005dcc0b8af1bc1f3b1204c88730a

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