Bug Fix and Rebuild All Stubs

* NuGet: Fixed #15: `WebClient.DownloadStringTaskAsync` can't create indirection stub. => The command `Get-IndirectionStubSetting` broke the serialized tag `Signature2` that contains a type information of another assembly. So, removed the procedure, and rethink the naming rule of indirection stub setting.
* All: Rebuild all stubs because the naming rule of indirection stub setting was changed.