Add link to ThunderSvmDotNet

[mjmckp]

I've created a .NET wrapper for ThunderSvm: https://github.com/mjmckp/ThunderSvmDotNet (also https://www.nuget.org/packages/ThunderSvmDotNet/1.0.0), perhaps you would like to add a link to this in the documentation?

[zeyiwen]

Thanks for the effort! This is a very valuable interface. We are figuring out a way to integrate your wrapper into this repository (e.g., adding a csharp folder), such that maintenance and upgrade can be handled more easily.