title: Classes used in a project
body: <p>Is there an elegant way to get a list of classes used in a project? </p>
  
  <p>I am aware of <code>objc_getClassList(...)</code> which gets all the classes in Objective-C, and I am trying to avoid using <code>class_conformsToProtocol</code> to filter out classes.</p>
  
  <p>Thanks.</p>