title: iOS - file does not contain an armv7s slice
body: <p>I cannot build and test on devices because Xcode gives me this error:</p>
  
  <pre><code>ld: file is universal (3 slices) but does not contain a(n) armv7s slice: /.../Classes/AddThis/libAddThis.a for architecture armv7s
  </code></pre>
  
  <p>How do I update this library to support armv7s?</p>