title: QuartzCore/CAMetalLayer.h file not found
body: <p>I try to check out the new Samples from the new Metal API for iOS.
  When i download the code an open it in the XCode 6 Beta I'm getting the following error message:</p>
  
  <pre><code>QuartzCore/CAMetalLayer.h file not found
  </code></pre>
  
  <p>Do i need to add some other files or am I missing something else?
  The Metal API should be available in OSX 10.9.3.</p>
  
  <p>Is there any need to upgrade to Yosemite 10.10 Beta to run these examples?</p>