Fixed the check for duplicate names to ignore hidden return parameters.

Signed-off-by: Dimitar Dobrev <dpldobrev@yahoo.com>

src/Generator/Passes/CheckDuplicatedNamesPass.cs

@@ -39,7 +39,8 @@ namespace CppSharp.Passes
 
         private bool UpdateName(Method method)
         {
-            var @params = method.Parameters.Select(p => p.QualifiedType.ToString());
+            var @params = method.Parameters.Where(p => p.Kind != ParameterKind.HiddenStructureReturn)
+                                .Select(p => p.QualifiedType.ToString());
             var signature = string.Format("{0}({1})", Name,string.Join( ", ", @params));
 
             if (Count == 0)