Added a ToString() method to ASTRecord to get better debug output.

src/Generator/AST/ASTRecord.cs

@@ -48,6 +48,11 @@ namespace CppSharp.Generators.AST
         {
             get { return (T) Object; }
         }
+
+        public override string ToString()
+        {
+            return Value.ToString();
+        }
     }
 
     public class ASTRecordStack