title: How to detect microphone input permission refused in iOS 7
body: <p>I would like to detect when a user refused the microphone permission on my iOS application.
  I only get this value when I try to record the microphone: -120.000000 db</p>
  
  <p>But before to get this I have to set up an AVAudioSession. Is there another function?</p>
  
  <p>And I got this message in the output:
  <code>Microphone input permission refused - will record only silence</code></p>
  
  <p>Thanks.</p>