Add missing dispose calls

OpenRA.Mods.Cnc/Traits/World/ChronoVortexRenderer.cs

@@ -23,7 +23,7 @@ namespace OpenRA.Mods.Cnc.Traits
 		public override object Create(ActorInitializer init) { return new ChronoVortexRenderer(init.Self); }
 	}
 
-	public sealed class ChronoVortexRenderer : IRenderPostProcessPass
+	public sealed class ChronoVortexRenderer : IRenderPostProcessPass, INotifyActorDisposing
 	{
 		readonly Renderer renderer;
 		readonly IShader shader;
@@ -105,5 +105,11 @@ namespace OpenRA.Mods.Cnc.Traits
 
 			vortices.Clear();
 		}
+
+		void INotifyActorDisposing.Disposing(Actor self)
+		{
+			vortexSheet.Dispose();
+			vortexBuffer.Dispose();
+		}
 	}
 }