title: metamacros.h not found, ReactiveCocoa via CocoaPods
body: <p>When ReactiveCocoa is being installed with CocoaPods, some required files are missing:</p>
  
  <p>metamacros.h, imported in RACTuple.h
  EXTScope.h, imported in NSNotificationCenter+RACSupport.h</p>
  
  <p>I tried out different Versions: 2.1.8, 2.4.7, 2.5.0.</p>
  
  <p><strong>Steps to reproduce:</strong></p>
  
  <ul>
  <li>create a new Project with XCode, Single View Application, called "RCFail"</li>
  <li><p>add a Podfile to the directory with following content: </p>
  
  <p>pod 'ReactiveCocoa', '~> 2.4.7'</p></li>
  </ul>
  
  <p><em>(or any other version or now explicit version to get 2.5.0 right now)</em></p>
  
  <ul>
  <li>open the RCFail.xcworkspace with XCode 6.3.2</li>
  <li>build the project (or at least, try to build)</li>
  </ul>
  
  <p><strong>Compiler Output:</strong></p>
  
  <pre><code>RCError/Pods/ReactiveCocoa/ReactiveCocoa/RACTuple.h:10:9: 'metamacros.h' file not found
  RCError/Pods/ReactiveCocoa/ReactiveCocoa/NSNotificationCenter+RACSupport.m:10:9: fatal error: 'EXTScope.h' file not found
   #import "EXTScope.h"
  </code></pre>
  
  <p>Is there any way to use ReactiveCocoa with CocoaPods right now?</p>
  
  <p><img src="https://i.stack.imgur.com/Xkrg1.png" alt="enter image description here">
  <img src="https://i.stack.imgur.com/RBlng.png" alt="enter image description here"></p>