title: Run NUnit 2.5.5 tests in Gallio 3.1
body: <p>I'm trying to get Gallio running some existing NUnit tests but they're not showing in Gallio.  The assembly loads into Gallio fine and I can run them fine via Resharper within the VS IDE.</p>
  
  <p>I created a really simple NUnit test in VS and this also doesn't show so I know it's not something weird in my existing tests.</p>
  
  <p>Any ideas?</p>