Mandatory gun update (#1685)

-added new sprites for rubber and rifles casings
-made bullets path less dumb
-added some new gun sprites, like the large crossbow and zipguns
-added a new tatical sprite mask, with support for unathi, tajaran and vox
-added back sprites for some items like bats and scythes
-fixed being able to saw off sawn-off shotguns forever and ever
-fixed a typo on the custom loadout
-nerfed the brain damage of the mind flayer, since brain damage is lethal now

code/modules/projectiles/projectile/special.dm

@@ -148,7 +148,7 @@
 	on_hit(var/atom/target, var/blocked = 0)
 		if(ishuman(target))
 			var/mob/living/carbon/human/M = target
-			M.adjustBrainLoss(20)
+			M.adjustBrainLoss(5)
 			M.hallucination += 20
 
 /obj/item/projectile/bullet/trod