What is the DNVM?

Im playing with the new VsCode editor, and created an ASPNET 5 template project. To restore the packages, I found in the tutorials that I need to run the dnu restore command, which gets all the server side references that I need.

After that, to build it I must run the dnx: web or kestrel command, and everything goes as expected.

But, what are those tools? In the git repository of the DNVM we dont have much information about it.

Does the dnu restore uses the nuget?

Someone have some complete documentation about all that in the new .NET?

I would like to know too if its possible to use the Roslyn compiler within the VSCode on Windows 8.1.