title: how to convert Glib::ustring to std::string?
body: <p>I cannot find any example on how to do this</p>
  
  <p>actually I just want to check if a ustring is equal to a constant string but it does not work</p>
  
  <pre><code>Glib::ustring somestring...
  if(somestring=="test")
    always returns true
  </code></pre>
  
  <p>thanks</p>