title: Mysterious protocol not implemented warning
body: <p>I am implementing a protocol that has a method called fbDidExtendToken:.
  For some reason, I get the warning that I am not implementing this method.
  Why is this?</p>
  
  <p>In my .h:</p>
  
  <pre><code>@interface AppDelegate : UIResponder &lt;UIApplicationDelegate, FBSessionDelegate&gt;
  //...
  </code></pre>
  
  <p>in my .mm</p>
  
  <pre><code>@implementation AppDelegate
  //...
  -(void)fbDidExtendToken:(NSString*)accessToken
  {
  
  }
  </code></pre>
  
  <p>Error message is:</p>
  
  <blockquote>
    <p>/Volumes/mchinen/scm/FindYourself/FindYourself/AppDelegate.mm:13:1:
    warning: method in protocol not implemented [-Wprotocol,3]
    /Volumes/mchinen/scm/FindYourself/src/Facebook.h:123:1: note: method
    declared here [3]
     - (void)fbDidExtendToken:(NSString*)accessToken</p>
  </blockquote>