title: Get resource URL from project specific path
body: <p>I need to retrieve the URL of a resource contained in my Xcode project through a path that begins in the project's directory (aka mainBundle)</p>
  
  <p>So if my specified path if ./snd/archer/acknowledge1.wav, I need to create a URL from that. </p>
  
  <p>I know I can use <code>NSURL(fileURLWithPath:)</code> for system directories, but I don't know how to do this directly from the bundle.</p>