Is there support for equivalent of .csproj ImplicitUsings? Could it be added? #719

I was debugging a compile error with a dotnet-script file and finally realized there was a missing using.
The program worked in a cs project and I then remembered that the default is now

<ImplicitUsings>enable</ImplicitUsings>

That would be a nice to have feature in dotnet-script. Or perhaps it's there and I don't know how to set it.