Cluster bomb launcher replacement

A simple modification to the cluster bomb launcher: replaces its projectile with a tank shell.  Also uses the appropriate sound effects, tracer and muzzle flash.  Includes a sniper scope zoom for long range attacks.

I had originally intended for it to have limited ammo, unfortunately infinite ammo appears to be hard coded to the bullet type so it is stuck with infinite.

Installation: Place the new pc_20.arc and pc_20.tab in your Just Cause 2\DLC folder (you may want to backup the originals first). Note: You must own the Cluster Bomb Launcher DLC for this mod to work.