Windows project out of date W.R.T. WindowsGL

I noticed the Windows project is missing a good deal of code present in the WindowsGL project. A couple of questions:

* I see Protobuild support arriving after #1945 is accepted. Should I still go ahead and submit a PR to bring the Windows project up to date before then?
* Should tests be written that cover all published XNA APIs (whether implemented or not)? Also for APIs specific to MonoGame?