This commit fixes also peculiar behavior of
$ slabtop -d 0
which did not make sense. The fix is to disallow anything else but
positive integers, which includes zero as is is not positive (or
negative) number.
Signed-off-by: Sami Kerola <kerolasa@iki.fi>
Using ncurses initscr/endwin clears the screen for xterm/etc it
now prints raw text using printf
Bug-Debian: http://bugs.debian.org/503089
Author: Craig Small <csmall@debian.org>