Try and clean up cycle detection output a bit

fml/common/cpw/mods/fml/common/DummyModContainer.java

@@ -157,4 +157,10 @@ public class DummyModContainer implements ModContainer
     {
         return null;
     }
+
+    @Override
+    public String toString()
+    {
+        return md != null ? getModId() :"Unknown Dummy Container @" + System.identityHashCode(this);
+    }
 }

fml/common/cpw/mods/fml/common/InjectedModContainer.java

@@ -148,4 +148,10 @@ public class InjectedModContainer implements ModContainer
     {
         return wrappedContainer.getSigningCertificate();
     }
+
+    @Override
+    public String toString()
+    {
+        return "Wrapped{"+wrappedContainer.toString()+"}";
+    }
 }

fml/common/cpw/mods/fml/common/toposort/TopologicalSort.java

@@ -25,6 +25,10 @@ import java.util.Set;
 import java.util.SortedSet;
 import java.util.TreeSet;
 
+import com.google.common.collect.Sets;
+
+import cpw.mods.fml.common.FMLLog;
+
 /**
  * Topological sort for mod loading
  *
@@ -174,7 +178,12 @@ public class TopologicalSort
                 return;
             }
 
-            System.out.printf("%s: %s\n%s\n%s\n", node, sortedResult, visitedNodes, expandedNodes);
+            FMLLog.severe("Mod Sorting failed.");
+            FMLLog.severe("Visting node %s", node);
+            FMLLog.severe("Current sorted list : %s", sortedResult);
+            FMLLog.severe("Visited set for this node : %s", visitedNodes);
+            FMLLog.severe("Explored node set : %s", expandedNodes);
+            FMLLog.severe("Likely cycle is in : %s", Sets.difference(expandedNodes, visitedNodes));
             throw new ModSortingException("There was a cycle detected in the input graph, sorting is not possible", node, visitedNodes);
         }