title: RestKit and AFNetworking build error
body: <p>When I attempt to import the RestKit api into a project I get the following error:</p>
  
  <pre><code>  /Documents/Code/RestTest/RestKit/Code/Network/RKHTTPRequestOperation.h:21:9:
   'AFNetworking.h' file not found
  </code></pre>
  
  <p>I have installed RestKit as a git submodule, how do I resolve RestKit's dependency on AFNetworking?</p>