title: Generate "never-expire" access token for Facebook Page
body: <p>I have managed to post to Facebook Page via API (C#), but when administrator of the page logs out, the following error occurs:</p>
  
  <p>"(OAuthException - #190) Error validating access token: The session is invalid because the user logged out."</p>
  
  <p>How do I generate access token which is never expired?</p>
  
  <p>I need a solution that doesn't open Facebook Login dialog.</p>