Merge FileFormats dll into Game and reorganise namespaces.

OpenRA.Mods.RA/Move/PathFinder.cs

@@ -12,7 +12,7 @@ using System;
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
-using OpenRA.FileFormats;
+using OpenRA.Primitives;
 using OpenRA.Support;
 using OpenRA.Traits;