title: missing android.jar in visual studio 2013
body: <p>I'm trying to use mono for android in vs.net 2013.
  when running the project, it says:</p>
  
  <p>Error   1   Could not find android.jar for API Level 8. This means the Android SDK platform for API Level 8 is not installed. Either install it in the Android SDK Manager (Tools > Open Android SDK Manager...), or change your Xamarin.Android project to target an API version that is installed. (C:\Users\M.K_Soft\AppData\Local\Android\android-sdk\platforms\android-8\android.jar missing.)</p>