Letting a package have control over it's presence in the UPackageMap object without
requiring it to be in 'ServerPackages' list.

WARNINGS:
This method crashes servers not running XC_Engine if not coded the following way.
This method only works before the first Tick, so do it while mutators are initializing.
Make sure this method isn't called on clients, may crash windows clients.

The function needs to be declared on the class about to use it, the compiler won't
complain about it and you'll be able to call it without problems if the opcode (1718)
is defined.

In order to prevent a call when said opcode isn't defined (Win32 client, no XC_Engine)
We simply perform a sanity check and make the mod not depend on XC_Engine at all!

AddToPackageMap works in two different ways:
- PkgName specified: attempts to load said package and add to Send list.
- PkgName unspecified: adds the actor's own package to Send list.
Adding a package to the UPackageMap object will automatically add all of it's
dependancies as well, so if you have a master package that (statically) loads others,
simply add that one package and the others will be inserted as well.

This method cannot force packages marked as ServerSide-Only to be sent.

====================
class MyMutator expands Mutator;

native(1718) final function bool AddToPackageMap( optional string PkgName);

event PostBeginPlay()
{
	if ( int(ConsoleCommand("XC_Version")) >= 11 )
		AddToPackageMap();
}
====================
