title: Proguard shrinking and optimizing without obfuscation
body: <p>In my app I have library project dependency with lots of unused methods fields and classes. Since this is a third-party library I don't want to remove all unused classes and methods by myself due it's future updates. I'm trying to use proguard for this but</p>
  
  <pre><code>-dontobfuscate
  </code></pre>
  
  <p>will only exclude whole project from any optimisations shrinking and obfuscation.
  Is it possible to skip obfuscation step?</p>