title: appcompat_v7.jar is missing
body: <p>I am a fresh android developer. And when I create a new "Android Application Project", the minimum SDK is API7. The configuration is shown as below:
  <img src="https://i.stack.imgur.com/Ol416.jpg" alt="enter image description here"></p>
  
  <p>But after configuration, here is a problem that "appcompat_v7.jar" in Android Dependencies is missing. Someone can solve it?
  <img src="https://i.stack.imgur.com/veTQZ.jpg" alt="enter image description here"></p>