Refactoring pass.

- Extract an enum for edges rather than using magic numbers for everything.
- Remove duplicated code between FoggedEdges and ShroudedEdges by hosting the visibility function into a delegate.
- Make minimap methods more readable.
- Tidy formatting.
- Make some fields readonly.
- Remove unused usings.

OpenRA.Mods.RA/Modifiers/FrozenUnderFog.cs

@@ -1,6 +1,6 @@
 #region Copyright & License Information
 /*
- * Copyright 2007-2013 The OpenRA Developers (see AUTHORS)
+ * Copyright 2007-2014 The OpenRA Developers (see AUTHORS)
  * This file is part of OpenRA, which is free software. It is made
  * available to you under the terms of the GNU General Public License
  * as published by the Free Software Foundation. For more information,
@@ -28,13 +28,16 @@ namespace OpenRA.Mods.RA
 	{
 		[Sync] public int VisibilityHash;
 
-		bool initialized, startsRevealed;
+		readonly bool startsRevealed;
 		readonly CPos[] footprint;
-		Lazy<IToolTip> tooltip;
-		Lazy<Health> health;
 
-		Dictionary<Player, bool> visible;
-		Dictionary<Player, FrozenActor> frozen;
+		readonly Lazy<IToolTip> tooltip;
+		readonly Lazy<Health> health;
+
+		readonly Dictionary<Player, bool> visible;
+		readonly Dictionary<Player, FrozenActor> frozen;
+
+		bool initialized;
 
 		public FrozenUnderFog(ActorInitializer init, FrozenUnderFogInfo info)
 		{