New bullet types, projectile rewrite

* Refactors projectile Bump()
* Converts projectile_type var strings to paths
* Reorganizes bullet projectile paths
* Made a pass through all the bullet_act() definitions. Mainly ensured that damage_type is checked when dealing damage to certain objects. Removed stupid /turf bullet_act() override, replaced with on_hit() overrides on the relevant projectiles.

* Adds shotgun pellets projectile. Adds Raptor's shotgun slug sprite.
* Gives stunshots more of their own identity, refluffs them as taser cartridges for shotguns. They still aren't obtainable anywhere unless spawned.
* Makes projectiles pass through girders and cultgirders with a certain probability, unless the girder itself was clicked.
* Projectiles are also able to pass through grilles. Low damage projectiles have a chance to be blocked by grilles. High damage projectiles have a chance to have some damage absorbed by the grille.
* Makes projectiles for blanks invisible.
* Adds flash bullet types
* Adds support for 'penetrating' projectiles
* Swaps .45 and 9mm projectile types. .45s hit slightly harder, 9mils have more ammo capacity.

code/game/objects/structures/inflatable.dm

@@ -38,6 +38,9 @@
 	return 0
 
 /obj/structure/inflatable/bullet_act(var/obj/item/projectile/Proj)
+	if(!(Proj.damage_type == BRUTE || Proj.damage_type == BURN))
+		return
+	
 	health -= Proj.damage
 	..()
 	if(health <= 0)