Replaced Knighthawk heli patrol with 2 Hueys

Apparently Knighthawks don't give a shit and just fly around. Never
actually attacking anyone. Even if fired upon. So I replaced it with 2
Hueys, for a total of 3.
DZMS NVG Fix

DZMS removes NVGs from AI when killed. I disabled that.
Barracks sniper spawning tweak

Tweaked the way snipers spawn sniper rifles due to 50 cals being WAY too
common. So ALL snipers now have a 0.5% chance of spawning.