title: NUnit not specified as test runner for SpecFlow
body: <p>For the life of me I cannot get SpecFlow configured to use NUnit as the test runner.  NUnit is not listed in the Tools > Options > SpecFlow test runner dropdown, and the "auto" setting doesn't find NUnit.</p>
  
  <p>I've tried reinstalling both NUnit and SpecFlow multiple times.  Tried installing SpecFlow 1.8.1 and 1.9 to no avail.  Tried using app.config.  I've even tried re-installing Visual Studio 2010.</p>
  
  <p>I just want SpecFlow to use NUnit (2.6.1).  Can anyone help?</p>