Enable concrete type for ISet<T> on WP-SL.

Author: yfakariya

src/MsgPack/Serialization/DefaultConcreteTypeRepository.cs

@@ -59,9 +59,9 @@ internal DefaultConcreteTypeRepository()
 					{ typeof( ICollection ).TypeHandle, typeof( List<MessagePackObject> ) },
 					{ typeof( IList ).TypeHandle, typeof( List<MessagePackObject> ) },
 					{ typeof( IDictionary ).TypeHandle, typeof( MessagePackObjectDictionary ) },
-#if !NETFX_35 && !WINDOWS_PHONE && !UNITY
+#if !NETFX_35 && !UNITY
 					{ typeof( ISet<> ).TypeHandle, typeof( HashSet<> ) },
-#endif // !NETFX_35 && !WINDOWS_PHONE && !UNITY
+#endif // !NETFX_35 && !UNITY
 				} );
 		}