cleaning up a bunch of stuff; silo works sensibly now

OpenRa.Game/Game.cs

@@ -10,8 +10,8 @@ namespace OpenRa.Game
 	class Game
 	{
 		public readonly World world;
-		public readonly Map map;
-		public readonly TreeCache treeCache;
+		public readonly Map map;
+		readonly TreeCache treeCache;
 		public readonly TerrainRenderer terrain;
 		public readonly Viewport viewport;
 		public readonly PathFinder pathFinder;