title: use of unresloved identifier FIRMessaging
body: <p>I'm facing a strange issue during integration of the Firebase Notification new API in my iOS Swift App.
  I encounter some difficulties receiving a push Notification sent from the Firebase web plateform. My certificate is OK since I tested it with a quick PHP script to send a test notification to my phone.</p>
  
  <p>In this post : <a href="https://stackoverflow.com/a/37467793/5082848">https://stackoverflow.com/a/37467793/5082848</a> , it is said to add in AppDelegate</p>
  
  <pre><code>func applicationDidBecomeActive(application: UIApplication) {
      FIRMessaging.messaging().connectWithCompletion { error in
          print(error)
      }
  }
  </code></pre>
  
  <p>However, <strong>FIRMessaging is unknown</strong>, whereas my podfile correctly contains Firebase/Messaging . Here is what the terminal returns after pod install :</p>
  
  <p>Using Firebase (3.3.0)</p>
  
  <p>Using FirebaseAnalytics (3.2.1)</p>
  
  <p>Using FirebaseInstanceID (1.0.7)</p>
  
  <p>Using GoogleInterchangeUtilities (1.2.1)</p>
  
  <p>Using GoogleSymbolUtilities (1.1.1)</p>
  
  <p>Using GoogleUtilities (1.3.1)</p>
  
  <p><strong>Do you have any clue please ? Thanks a lot</strong></p>