title: Errors trying to use AdWhirl with Admob
body: <p>I am trying to setup a test application for AdWhirl to see how this functions etc. I have setup a new application in Xcode which just loads a single view.</p>
  
  <p>I have downloaded and added the latest SDK for AdWhirl then removed all the folders in adapters I am not using...Per step 4 - <a href="https://www.adwhirl.com/doc/ios/AdWhirliOSSDKSetup.html" rel="noreferrer">https://www.adwhirl.com/doc/ios/AdWhirliOSSDKSetup.html</a></p>
  
  <p>I have then downloaded the SDK for AdMob and setup a new application on Admob, entering the relevant pub ID into the settings for AdWhirl... still with me?</p>
  
  <p>Without making any further changes to the app itself I am getting build errors below:</p>
  
  <pre><code>Undefined symbols for architecture i386:
  "_OBJC_CLASS_$_SKStoreProductViewController", referenced from:
    objc-class-ref in libGoogleAdMobAds.a(GADOpener.o)
  "_SKStoreProductParameterITunesItemIdentifier", referenced from:
    -[GADOpener openInAppStore:fallbackURLString:] in libGoogleAdMobAds.a(GADOpener.o)
  </code></pre>
  
  <p>ld: symbol(s) not found for architecture i386
  clang: error: linker command failed with exit code 1 (use -v to see invocation)</p>
  
  <p>I have all the relevant libraries included picture to show. Also included a pic to show the layout of files. </p>
  
  <p>Has anyone had this issue and can help. A lot of the posts on here say to check MessageUI framework and check build settings for framework search paths but this is all fine in this case...</p>
  
  <p><img src="https://i.stack.imgur.com/34tDE.png" alt="enter image description here"></p>
  
  <p><img src="https://i.stack.imgur.com/w0Drh.png" alt="enter image description here"></p>