Fixed SetMethodParameterUsage to use complete class declarations.

src/Generator/Library.cs

@@ -257,8 +257,7 @@ namespace CppSharp
             if (parameterIndex <= 0 )
                  throw new ArgumentException("parameterIndex");
 
-            foreach (var @class in context.FindClass(className))
+            var @class = context.FindCompleteClass(className);
-            {
             var method = @class.Methods.Find(m => m.Name == methodName);
             if (method == null)
                 throw new ArgumentException("methodName");
@@ -267,7 +266,6 @@ namespace CppSharp
 
             method.Parameters[parameterIndex - 1].Usage = usage;
         }
-        }
 
         public static void CopyClassFields(this ASTContext context, string source,
             string destination)