title: Spotify Beta 5 SDK for iOS crashes when trying to play iTunes playlist
body: <p>Using the Spotify iOS SDK Beta 5, when I request playlists using the method:</p>
  
  <pre><code>[SPTRequest playlistsForUserInSession:self.session callback:^(NSError *error, id object) {
      self.playlists = ((SPTListPage*)object).items;
  }];
  </code></pre>
  
  <p>I get a list back that contains both native Spotify and iTunes playlists that the Spotify desktop app assimilated.  There is nothing in the list entries to disambiguate them.  If I try to play one of the iTunes playlists using code like this:</p>
  
  <pre><code>[SPTRequest requestItemAtURI:uri
                   withSession:session
                      callback:^(NSError *error, id object) {
  
                          if (error != nil) {
                              NSLog(@"*** got error %@", error);
                              return;
                          }
  
                          [self.streamer playTrackProvider:object callback:^(NSError *error) {
                              NSLog (@"*** reached callback");
                          }];
  
                      }];
  </code></pre>
  
  <p>My app crashes in the Spotify SDK, with this error:</p>
  
  <pre><code>-[NSNull caseInsensitiveCompare:]: unrecognized selector sent to instance 0x198ba9fe0
  </code></pre>
  
  <p>and this stack trace:</p>
  
  <pre><code>Thread 10, Queue : com.apple.root.default-priority
  #0  0x000000019816c1c0 in objc_exception_throw ()
  #1  0x000000018bc67db4 in -[NSObject(NSObject) doesNotRecognizeSelector:] ()
  #2  0x000000018bc65ae0 in ___forwarding___ ()
  #3  0x000000018bb8578c in _CF_forwarding_prep_0 ()
  #4  0x0000000100099d40 in -[SPTPartialAlbum initWithDecodedJSONObject:error:] at /Users/po/Projects/ios-sdk/src/SPTPartialAlbum.m:85
  #5  0x00000001000a6578 in +[SPTJSONDecoding SPObjectFromDecodedJSON:collection:error:] at /Users/po/Projects/ios-sdk/src/SPTJSONDecoding.m:95
  #6  0x000000010008bd2c in -[SPTTrack initWithDecodedJSONObject:error:] at /Users/po/Projects/ios-sdk/src/SPTTrack.m:83
  #7  0x000000010008a350 in -[SPTPlaylistTrack initWithDecodedJSONObject:error:] at /Users/po/Projects/ios-sdk/src/SPTPlaylistTrack.m:44
  #8  0x00000001000a6578 in +[SPTJSONDecoding SPObjectFromDecodedJSON:collection:error:] at /Users/po/Projects/ios-sdk/src/SPTJSONDecoding.m:95
  #9  0x0000000100096ebc in -[SPTListPage initWithDecodedJSONObject:expectingPartialChildren:rootObjectKey:] at /Users/po/Projects/ios-sdk/src/SPTListPage.m:84
  #10 0x000000010008fcac in -[SPTPlaylistSnapshot initWithDecodedJSONObject:error:] at /Users/po/Projects/ios-sdk/src/SPTPlaylistSnapshot.m:137
  #11 0x00000001000a6578 in +[SPTJSONDecoding SPObjectFromDecodedJSON:collection:error:] at /Users/po/Projects/ios-sdk/src/SPTJSONDecoding.m:95
  #12 0x00000001000a1664 in __56+[SPTRequest requestPlaylistAtURI:withSession:callback:]_block_invoke at /Users/po/Projects/ios-sdk/src/SPTRequest.m:595
  #13 0x0000000198744014 in _dispatch_call_block_and_release ()
  #14 0x0000000198743fd4 in _dispatch_client_callout ()
  #15 0x000000019874b2b8 in _dispatch_root_queue_drain ()
  #16 0x000000019874b4fc in _dispatch_worker_thread2 ()
  #17 0x00000001988d96bc in _pthread_wqthread ()
  </code></pre>
  
  <p>Native Spotify playlists play fine.</p>
  
  <p>Help!  Is there a workaround for this?  I don't think that iTunes playlists should be returned by the SDK when requesting playlists.  Or, give me something that I can use to determine which playlists are iTunes based, so I can hide them from the user of my iOS app.  Or, don't crash in the SDK when trying to play one.</p>
  
  <p>Spotify SDK developers: Help!?  The previous SDK showed the iTunes playlists, but didn't crash when requesting one via requestItemAtURI.</p>