v4.0.0-pre3

New In This Release:

• Added Support for ValueTask in SafeFireAndForget
• Added Support for ValueTask
• Added IAsyncValueCommand : ICommand
• Added AsyncValueCommand : IAsyncValueCommand
• Added IAsyncValueCommand<T>; : ICommand
• Added AsyncValueCommand<T>; : IAsyncValueCommand<T>
• Added RaiseCanExecuteChanged to IAsyncCommand and IAsyncValueCommand