Fix setfib(1) section number.

- use a format string in a printf()
- move a variable declaration at the beginning of a block
- const-ify strings
- fix prototypes

The only new feature is that now one can write
"table all {flush | list}" to act on all tables.

Just for the records, there is one difference which probably
has no practical importance; two "tos" flags are represented
differently now:

@@ -182,8 +182,8 @@ static struct _s_x f_iptos[] = {
 	{ "throughput",	IPTOS_THROUGHPUT},
 	{ "reliability", IPTOS_RELIABILITY},
 	{ "mincost",	IPTOS_MINCOST},
-	{ "congestion",	IPTOS_CE},
-	{ "ecntransport", IPTOS_ECT},
+	{ "congestion",	IPTOS_ECN_CE},
+	{ "ecntransport", IPTOS_ECN_ECT0},
 	{ "ip tos option", 0},
 	{ NULL,	0 }
 };

IPTOS_ECT = IPTOS_ECN_ECT0 = 2 so 'ecntransport' is the same.

IPTOS_CE = 1, IPTOS_ECN_CE = 3 so 'congestion' is represented by a
different codepoint, but this also reflects a different specification
(RFC3168 obsoletes RFC2481) so the change is just adopting the new
spec.

Honor the quiet (-q) option while adding a nat rule.

 New Revision: 182818
 URL: http://svn.freebsd.org/changeset/base/182818

 Log:
  Export the IPFW_DEFAULT_RULE outside ip_fw2.c.  This number in not only
  the default rule number but also the maximum rule number.  User space
  software such as ipfw and natd should be aware of its value.  The
  software that already includes ip_fw.h should use the defined value.  All
  other a expected to use sysctl (as discussed on net@).

  MFC after: 5 days.
  Discussed on: net@

 Modified:
  head/sys/netinet/ip_fw.h
  head/sys/netinet/ip_fw2.c

 New Revision: 182823
 URL: http://svn.freebsd.org/changeset/base/182823

 Log:
  Use IPFW_DEFAULT_RULE instead of hardcoded value since now it is
  available.

  MFC after:    5 days.

 Modified:
  head/sbin/ipfw/ipfw2.c

 New Revision: 182825
 URL: http://svn.freebsd.org/changeset/base/182825

 Log:
  Check rule numbers against maximum value to avoid rules cleanup due
  to overflow.

  MFC after:    5 days.

 Modified:
  head/sbin/natd/natd.c

 New Revision: 183012
 URL: http://svn.freebsd.org/changeset/base/183012

 Log:
  Make the commet for the default rule number more clear.

  Submitted by:    yar@

 Modified:
  head/sys/netinet/ip_fw.h

Approved by:	re (kensmith)

This was already supported in userland.