I have the same question and am not going to be able to use this tool until I can figure it out. I am using netstandard1.4 and I've tried to change the value of the "imports" element in project.json, but no joy. I really don't want to have to write a whole abstraction layer for my Xamarin Forms dll's to hide away the LinkOS object model, but I guess I will if I can't find a way around this.