Remove runtime mod merging. Closes #3421.

OpenRA.FileFormats/Mod.cs

@@ -21,7 +21,6 @@ namespace OpenRA.FileFormats
 		public string Description;
 		public string Version;
 		public string Author;
-		public string Requires;
 
 		public static readonly Dictionary<string, Mod> AllMods = ValidateMods(Directory.GetDirectories("mods").Select(x => x.Substring(5)).ToArray());
 
@@ -45,12 +44,5 @@ namespace OpenRA.FileFormats
 			}
 			return ret;
 		}
-
-		public string[] WithPrerequisites()
-		{
-			return Id.Iterate(m => AllMods[m].Requires)
-				.TakeWhile(m => m != null)
-				.ToArray();
-		}
 	}
 }