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/AI/HackyAI.cs

@@ -22,7 +22,7 @@ using OpenRA.Support;
 
 namespace OpenRA.Mods.RA.AI
 {
-	public class HackyAIInfo : IBotInfo, ITraitInfo
+	public sealed class HackyAIInfo : IBotInfo, ITraitInfo
 	{
 		public readonly string Name = "Unnamed Bot";
 		public readonly int SquadSize = 8;
@@ -90,7 +90,7 @@ namespace OpenRA.Mods.RA.AI
 
 	public enum BuildingType { Building, Defense, Refinery }
 
-	public class HackyAI : ITick, IBot, INotifyDamage
+	public sealed class HackyAI : ITick, IBot, INotifyDamage
 	{
 		bool enabled;
 		public int ticks;
@@ -157,7 +157,7 @@ namespace OpenRA.Mods.RA.AI
 				.Select(t => t.TerrainType).ToArray();
 		}
 
-		int GetPowerProvidedBy(ActorInfo building)
+		static int GetPowerProvidedBy(ActorInfo building)
 		{
 			var bi = building.Traits.GetOrDefault<BuildingInfo>();
 			return bi != null ? bi.Power : 0;