WHOX support for UnrealIRCD 4.

To install:
1. Add m_whox.c to your src/modules/third directory
2. Run `make`
3. Run `make install`
4. Add `loadmodule "third/m_whox"` to your conf
5. /rehash

This adds the token WHOX to the ISUPPORT reply and allows for specifying WHOX fields in /WHO commands.

To use:
`/WHO [+|-][acghimnsuMRI][%tcuihsnfdlar[,querytype]] [args] [mask]` OR `/WHO [mask] [+|-][acghimnsuMRI][%tcuihsnfdlar[,querytype]] [args]`

For a description of the flags (the parts before the %), see the built-in /WHO documentation. This module _replaces_ the built-in /WHO command, but retains its functionality in that regard. If the % character and fields are not specified, it operates exactly like the built-in /WHO command (returning a 352 numeric for each who reply).

Optionally, a % followed by fields can be specified in order to customize the output of /WHO. If a field is not specified, it is omitted from the output. When % and fields are specified, The ordering is fixed, and is in the order listed below:
 - t: outputs the number in querytype in reply
 - c: channel
 - u: username
 - i: IP address (255.255.255.255 if the IP is unknown, for example if the target is usermode +x and you are not an oper)
 - h: host
 - s: server
 - n: nickname
 - f: status
 - d: hop count
 - l: idle time (0 for users on other servers)
 - a: services account name (0 if none)
 - r: realname