Fix GCC warning: field precision specifier ‘.*’ expects argument of type ‘int’, but argument 3 has type ‘long unsigned int’ [-Wformat=]

Parse the attribute flags and print descriptions of the set flags
(except for unused bit-10).
Allow a '-c' option to only print control (kludge) lines from the body text.
The '-b' option displays both body text and control lines (same as before).
Fixed a memory leak and some other bad code examples.
Some minor beautifications.

But don't whine about EOF.

I'm lookin' at you, retronet.

and also look to see if the nodelist file exists before trying to
load it for a search.

Lock the mail base while backing it up as part of the daily maintenance.

is ever written to disk, it'll be zeroes not garbage.
Also, NULL the subscan pointer after freeing (and don't free if it's NULL).

is set: this insures that uninitialized msg-scan ptrs/cfg won't be
written to disk unless a successful logon()/getmsgptrs() was called first.
This probably fixes the sighting that echicken reported where a failed
SSH login caused his sub-scan config file (data/user/0001.subs) to contain
uninitialized/garbage values.
logout() could be called from multiple places (e.g. JS and Baja modules),
even before a successful login is completed, so this sighting is not
entirely impractical.

With the change to smblib of March 14 (smbstr.c 1.29), netaddr_type() will
parse generic words as QWK-network addresses. The fix here is to only
attempt a net-type lookup if the 'to' field contains an '@'.

Front-pad cell contents with 2+ spaces for right align.
Pad each end with 2+ spaces for centre align.
No attempt has been made to make this play nicely with colspans,
but it does work with wrapped cells.

domain name from sbbsecho.ini), use its value as the domain name in the
lightbar list.
For nodelist_DomainName keys, use the DomainName portion as the domain
name in the lightbar list.
(Don't use the parsed domain name from the nodelist file's first line,
this is unreliable.)

log the filename and error if one occurs.

Replaces 'ftnnv' thing that's been floating around.
Loads any nodelists you've configured in echocfg/sbbsecho.ini.
Has a search feature, let's you send netmail.

You can optionally add this section and any keys to modopts.ini:

[fido_nodelist_browser]
auto_close_domain = true
auto_close_zone = true
auto_close_net = true
nodelist_a = /path/to/some/nodelist
nodelist_b = /path/to/some/other/nodelist

The auto_close settings control whether branches in the lightbar tree are
closed when you open another at the same level.  The defaults are more
memory friendly.

If you have nodelists not known to sbbsecho (or aren't using sbbsecho 3)
you can add them here; the key must begin with 'nodelist_'.  Wildcards
are not supported; you should have some external mechanism copying the
current nodelist to a fixed path & filename.

record in the node.dab - only the node(s) that have the requested user
number.
In sbbs_t::getsmsg() and ::getsmsg(), strip all invalid Ctrl-A attribute
codes (e.g. clear screen, pause, etc.) since short-messages (telegrams)
can come from external sources.

Double the duration to wait for client threads to terminate. Heck, this might
should be an infinite wait since "bad things" happen if the client thread
continues after a cleanup().

actual message number (rather than a 1-based message index offset) by using
#<number>, e.g. "smbutil r#3694" will read the message base starting at
message number 3694, if it exists.

Also documented the [-n] syntax for reading/listing messages less than
n days old.

with the terminal and mail servers' log output and provide more details
(e.g. on errors).

separate from the log text and is consistent with the mail server log
output.

alphabetized, so the indexes don't necessarily match the order (of timed
events) in SCFG.

Don't use the word "module".