I’ve been following Lucian Wischik’s interesting series of posts on writing Windows 10 applications in .NET. While I was on holiday he posted an article on writing NuGet packages for UWP but unfortunately the article was removed from the web site when I was only half a way through it. The place holder mentions that the NuGet team were going to talk about the issues and, sure enough, a post has now appeared on NuGet support for UWP in NuGet 3.1. In summary you will now be able to declare project references using a project.json (in much the same way as ASP.NET 5 projects). This will also use the transitive references idea, where you list only the top level projects that you require, and NuGet will take care of fetching their dependencies (and also resolve the appropriate versions when there are conflicts), in contrast to the current model where dependencies of dependencies make their way into your packages.config.
Finally, if Windows Update fails to install Windows 10 repeatedly), then this post has the answer, or rather it works for some people. For me, the relaunched Windows Update failed again, so in the end I needed to manually download by following this link.