Issue #668: Sample should be covered by a basic functional test.

#668 - Adding tests for a couple of Controllers in the sample.
My point is that we we **know** that `ApplicationBasePath` is `Mvc/test/Microsoft.AspNet.Mvc.FunctionalTests`. That's a guarantee of the runtime.

The value of `$pwd` just *happens* to be `Mvc/test/Microsoft.AspNet.Mvc.FunctionalTests` based on how our build system is doing things. It's better to depend on something that's guaranteed rather than something that may change.