Moved xpDateTime and isoDateTime functions from datewrap.* to xpdatetime.*.
Created several new xp and ISO date time functions and macros.

Numerous bounds-checking additions.

server.

Was using the wrong condition to test if we should start interpreting from
the start of the string... would cause problems for strings ending in a CR

Ensure that node messages and telegrams are delivered during input.

at the start of the function rather than at the end.

Also, for sbbs_t.getsmsg() clear the node.misc bits for all nodes with
the to user rather than just the current node.

Do not allow invalid text entry.

real-time interaction.

to be RFC-822 (or RFC-977) compliant.
Added smb_netaddrstr() for a thread-safe version of smb_netaddr().

being C99 compliant).

path the scrip was started from.

the startup path.

inactive users to persist until they are killed, use a %04d.tw2 file in
data/users to track that it is the "right" user by that number.

Move user deletion "stuff" into a separate function.

in sector rather than reading the entire player database.

This allows using a private DNS server when an external interface is specified
(ie: DNS Server of 127.0.0.1 with an interface address specified)