Introducing per-player shrouds.

- Each player has their own shroud and their visibility does not extend outside of the shroud. 
- Units and buildings can no longer target other units outside of their visibility. Buildings can still be targetted if they have been explored.
- GPS will provide visibility in the fog-of-war.
- Spies that infiltrate radar domes will gain their victim's exploration and reset it on all clients (if the victim does not have GPS)

OpenRA.Mods.RA/Widgets/WorldTooltipWidget.cs

@@ -33,7 +33,7 @@ namespace OpenRA.Mods.RA.Widgets
 			var cell = Game.viewport.ViewToWorld(Viewport.LastMousePos);
 			if (!world.Map.IsInMap(cell)) return;
 
-			if (world.LocalPlayer != null && !world.LocalPlayer.Shroud.IsExplored(cell))
+			if (world.LocalPlayer != null && !world.RenderedShroud.IsExplored(cell))
 			{
 				var utext = "Unexplored Terrain";
 				var usz = Game.Renderer.Fonts["Bold"].Measure(utext) + new int2(20, 24);