title: AVAudioSession output selection
body: <p>If multiple input &amp; output accessories are attached to iPhone, I want the user to be able to manually select the input &amp; output source. I can manually select input by querying [[AVAudioSession sharedInstance] availableInputs] and then using setPreferredInput:error method in iOS 7, but I can not find anything similar for output. How do I achieve this ? I am using PlayAndRecord category.</p>