title: card.io will not compile on 64bit iPhone 5s armv7s
body: <p>I'm having trouble compiling card.io on an iPhone 5s in 64bit mode (armv7s). It will compile on the simulator just finw. I am using Xcode 5.</p>
  
  <p>Here is my error message:</p>
  
  <pre class="lang-none prettyprint-override"><code>Undefined symbols for architecture armv7s:
    "_CMSampleBufferGetImageBuffer", referenced from:
        -[CardIOVideoFrame process] in libCardIO.a(CardIOVideoFrame.o)
    "_CMGetAttachment", referenced from:
        -[CardIOVideoStream captureOutput:didOutputSampleBuffer:fromConnection:] in libCardIO.a(CardIOVideoStream.o)
  ld: symbol(s) not found for architecture armv7s
  </code></pre>