Add support for multiple explosions to CreateEffectWarhead

Have the engine pick one explosion at random from the provided list.

mods/cnc/weapons/smallcaliber.yaml

@@ -28,7 +28,7 @@ HighV:
 			Heavy: 35
 		DamageTypes: Prone50Percent, TriggerProne, BulletDeath
 	Warhead@2Eff: CreateEffect
-		Explosion: piffs
+		Explosions: piffs
 
 HeliAGGun:
 	ReloadDelay: 20
@@ -52,7 +52,7 @@ HeliAGGun:
 			Heavy: 25
 		DamageTypes: Prone50Percent, TriggerProne, BulletDeath
 	Warhead@2Eff: CreateEffect
-		Explosion: piffs
+		Explosions: piffs
 
 HeliAAGun:
 	ReloadDelay: 20
@@ -76,7 +76,7 @@ HeliAAGun:
 			Heavy: 25
 		DamageTypes: Prone50Percent, TriggerProne, BulletDeath
 	Warhead@2Eff: CreateEffect
-		Explosion: piffs
+		Explosions: piffs
 
 Pistol:
 	ReloadDelay: 7
@@ -96,7 +96,7 @@ Pistol:
 			Heavy: 25
 		DamageTypes: Prone50Percent, TriggerProne, BulletDeath
 	Warhead@2Eff: CreateEffect
-		Explosion: piff
+		Explosions: piff
 
 M16:
 	ReloadDelay: 20
@@ -116,7 +116,7 @@ M16:
 			Heavy: 10
 		DamageTypes: Prone50Percent, TriggerProne, BulletDeath
 	Warhead@2Eff: CreateEffect
-		Explosion: piff
+		Explosions: piff
 
 MachineGun:
 	ReloadDelay: 20
@@ -138,7 +138,7 @@ MachineGun:
 			Concrete: 10
 		DamageTypes: Prone50Percent, TriggerProne, BulletDeath
 	Warhead@2Eff: CreateEffect
-		Explosion: piffs
+		Explosions: piffs
 
 Vulcan:
 	ValidTargets: Ground, Water
@@ -158,7 +158,7 @@ Vulcan:
 			Heavy: 35
 		DamageTypes: Prone50Percent, TriggerProne, BulletDeath
 	Warhead@2Eff: CreateEffect
-		Explosion: piffs
+		Explosions: piffs
 
 APCGun:
 	ReloadDelay: 18
@@ -178,7 +178,7 @@ APCGun:
 			Heavy: 50
 		DamageTypes: Prone50Percent, TriggerProne, DefaultDeath
 	Warhead@2Eff: CreateEffect
-		Explosion: small_poof
+		Explosions: small_poof
 
 APCGun.AA:
 	ReloadDelay: 18
@@ -196,4 +196,4 @@ APCGun.AA:
 			Heavy: 50
 		DamageTypes: Prone50Percent, TriggerProne, DefaultDeath
 	Warhead@2Eff: CreateEffect
-		Explosion: small_frag
+		Explosions: small_frag