Initial setup

If you're wondering what this is all about, it's going to be a port of [this](http://bugsquash.blogspot.dk/2012/05/first-class-tests-in-mbunit.html) to xUnit.net. We need it to be able to write regression tests for Champagne in a sane way.

I already have a working prototype of this on my system, so it shouldn't turn into a wild goose chase.