getNullableType
* Fix default nullable * Fix tests * Update samples * Fix template default value * Update samples * Also fix for interface * update samples
* fix map type in csharp netcore * add new files for csharp netcore client
* update csharp default value * update csharp 35 samples * update csharp 40 client * update c# net standard client * update C# net core client * update csharp propertychanged client