NetStandard with ResX support?

[maxkatz6]

Hi!
Since lib generates WinRT related code and uses only ResW, we can't use it in NetStandard1.4 (or any else netstandard) projects.
I see, that repository is called 'ReswPlus', but it looks like self limitation.

I think next solution:

1. If developer is initializing ReswPlus on .resw file - then use WinRT resources.
2. If developer is initializing ReswPlus on .resx file - then use .Net resources.
3. MarkupExtension and other platform specific classes could be in separated nuget package.

Someone could wish markup extensions for Xamarin/Wpf/Avalonia, but it could be implemented in future. WinRT dependency blocks it now.

Thanks.