explosions are more or less correct now

OpenRa.Game/GameRules/WarheadInfo.cs

@@ -16,6 +16,8 @@ namespace OpenRa.Game.GameRules
 		public readonly bool Ore = false;
 		public readonly int Explosion = 0;
 		public readonly int InfDeath = 0;
+		public readonly string ImpactSound = null;
+		public readonly string WaterImpactSound = null;
 
 		public float EffectivenessAgainst(ArmorType at) { return Verses[ (int)at ]; }
 	}