title: How do I make error-prone ignore my generated source code?
body: <p>I've recently discovered <a href="http://errorprone.info" rel="nofollow">Error Prone</a> and am integrating it into my Android build using the <a href="https://github.com/tbroyer/gradle-errorprone-plugin" rel="nofollow">Gradle plugin</a> linked on their page.</p>
  
  <p>Since our project is using Icepick (and some other code generating annotation processors), we have generated source code, which gets compiled in.  Unfortunately, some of the generated code triggers warnings in Error Prone, and I'd like to filter that noise out somehow. </p>
  
  <p>The generated code shows up in the <code>app/build/generated/source/apt/debug</code> directory.  How can I exempt this code from Error Prone's steely gaze?</p>