General uncontroversial cleanup:

- Made private methods static where possible (runtime can elide checking the object for null).
- Declared attribute classes as sealed (allows reflection on attributes to complete faster).
- Moved some static cctor's into field initializers (static cctor's are slower than static field initializers).
- Made classes static if they contained only static methods (can't create instances of useless objects).
- Use inferable Exts.Lazy and not new Lazy<T>().
- Added required STAThread attribute to CrashDialog.
- Removed unused parameters in private methods.
- Added Serializable attribute to exceptions.
- Added parameter name in calls to ArgumentNullException.
- Use of as operator instead of is + cast.
- Changed (x as Foo).Bar anti-pattern into ((Foo)x).Bar. Results in sensible cast exceptions on error rather than null dereferences.
- Removed unused method in NullShader.

OpenRA.Mods.RA/Crates/ExplodeCrateAction.cs

@@ -27,7 +27,7 @@ namespace OpenRA.Mods.RA
 
 		public override void Activate(Actor collector)
 		{
-			Combat.DoExplosion(self, (info as ExplodeCrateActionInfo).Weapon, collector.CenterPosition);
+			Combat.DoExplosion(self, ((ExplodeCrateActionInfo)info).Weapon, collector.CenterPosition);
 			base.Activate(collector);
 		}
 	}

OpenRA.Mods.RA/Crates/GiveCashCrateAction.cs

@@ -30,10 +30,11 @@ namespace OpenRA.Mods.RA
 		{
 			collector.World.AddFrameEndTask(w =>
 			{
-				var amount = (info as GiveCashCrateActionInfo).Amount;
+				var crateInfo = (GiveCashCrateActionInfo)info;
+				var amount = crateInfo.Amount;
 				collector.Owner.PlayerActor.Trait<PlayerResources>().GiveCash(amount);
 
-				if ((info as GiveCashCrateActionInfo).UseCashTick)
+				if (crateInfo.UseCashTick)
 					w.Add(new CashTick(collector.CenterPosition, collector.Owner.Color.RGB, amount));
 			});
 

OpenRA.Mods.RA/Crates/GiveMcvCrateAction.cs

@@ -32,7 +32,7 @@ namespace OpenRA.Mods.RA.Crates
 				.Any(a => a.Actor.Owner == collector.Owner);
 
 			return hasBase ? info.SelectionShares :
-				(info as GiveMcvCrateActionInfo).NoBaseSelectionShares;
+				((GiveMcvCrateActionInfo)info).NoBaseSelectionShares;
 		}
 	}
 }

OpenRA.Mods.RA/Crates/LevelUpCrateAction.cs

@@ -34,7 +34,7 @@ namespace OpenRA.Mods.RA
 			{
 				var gainsExperience = collector.TraitOrDefault<GainsExperience>();
 				if (gainsExperience != null)
-					gainsExperience.GiveLevels((info as LevelUpCrateActionInfo).Levels);
+					gainsExperience.GiveLevels(((LevelUpCrateActionInfo)info).Levels);
 			});
 
 			base.Activate(collector);

OpenRA.Mods.RA/Crates/RevealMapCrateAction.cs

@@ -25,7 +25,7 @@ namespace OpenRA.Mods.RA
 
 		bool ShouldReveal(Player collectingPlayer)
 		{
-			if ((info as RevealMapCrateActionInfo).IncludeAllies)
+			if (((RevealMapCrateActionInfo)info).IncludeAllies)
 				return collectingPlayer.World.LocalPlayer != null &&
 					collectingPlayer.Stances[collectingPlayer.World.LocalPlayer] == Stance.Ally;