New Features:
- Multiple bindings for each service
  Use comma-separated interfaces on Interface= lines in the ini file.
  Default is now "0.0.0.0,::"
- IPv6 support
- TLS support for the webserver and (non-static) services
  New TLS option in services.ini (ie: Options=TLS)
- Decrease LEN_SCAN_CMD to 35 chars, increase the CID field to 45 chars,
  and rename the MAIL_CMD string to IPADDR.  I think this frees up the
  note field for SysOp use.

getusrsub() returned the completely wrong sub-board number. It assumed that
getusrgrp() returned a 0-based index when in fact it returns a 1-based group
number. This bug was only visible when using certain @-codes (e.g. "SN",
"SL", "SR", and "SMB_SUB_NUM") when a sub-board was open via Synchronet
internal function (i.e. not via JS MsgBase class). If the current group was the
last group visible to the user, this would cause a crash.

DELETED keywords with other keywords (e.g. "NOT DELETED AND LEVEL 50)":
keyword/values following the broken keyword would be interpretted incorrectly.

Added HOST and IP keywords to allow restricted access/privileges to/for
specific remote hostnames or IP addresses (wildcards allowed).
All string-argument type ARS keywords (e.g. SHELL, PROT, etc.) now support .can
style wildcards.
The current remote client is now used for protocol, host, and IP ARS checking,
when available, so this requires passing the client pointer around (which
explains why so many files are touched by this change) and takes care of a
long standing to-do item (the user's 'modem' value was used for the PROT
value checking, which was not always correct).

by properly const-ifying the appropriate functions and variables.

Not yet tested on Win32

ULM (uploaded megabytes), and DLK and DLM (for downloaded K/Mbytes).

* ULS - uploaded files
* ULB - uploaded bytes
* DLS - downloaded files
* DLB - downloaded bytes

... so now Phil can have a "true" 1:4 upload/download file ratio requirement by
using an ARS of "DLS NOT 4 OR UDFR 25"

* GUEST (shorthand for "REST G")
* QNODE (shorthand for "REST Q").
They're not really much shorter, but the intended function is more clear to the
sysop.

(not rounded up to 100%).

correctly for the BBS (e.g. "Telnet" and "RLogin") until the chk_ar function is
changed to accept a client_t argument.

variants (gmtime_r, localtime_r, and ctime_r) for thread-safe operation on Unix

and group number for a specified (0-based) subnum.

additional keywords and parameters (if present) were not interpretted correctly.

GMT/UTC.

Created system call wrappers.c (and sbbswrap.h) and moved target platform-specific macros and code there.