Cache results of TraitsImplementing calls.

If a class is caching the TraitsImplementing enumerable, instead cache the results of enumerating it to an array. The avoids having to enumerate the sequence each time it is needed.

OpenRA.Game/GameRules/WeaponInfo.cs

@@ -19,8 +19,8 @@ namespace OpenRA.GameRules
 	public class ProjectileArgs
 	{
 		public WeaponInfo Weapon;
-		public IEnumerable<int> DamageModifiers;
-		public IEnumerable<int> InaccuracyModifiers;
+		public int[] DamageModifiers;
+		public int[] InaccuracyModifiers;
 		public int Facing;
 		public WPos Source;
 		public Actor SourceActor;