title: Android Picasso library, How to add authentication headers?
body: <p>I have tried setting a custom OkHttpClient with a custom Authenticator, however as the doc says: "Responds to authentication challenges from the remote web or proxy server." I have to make 2 requests for each image, and that is not ideal.</p>
  
  <p>Is there a request interceptor like Retrofit does? Or am I missing something in the OkHttpClient?</p>
  
  <p>I'm using the latest versions:</p>
  
  <pre><code>compile 'com.squareup.picasso:picasso:2.3.2'
  compile 'com.squareup.okhttp:okhttp:2.0.+'
  compile 'com.squareup.okhttp:okhttp-urlconnection:2.0.+'
  compile 'com.squareup.okio:okio:1.0.0'
  </code></pre>
  
  <p>Thanks!</p>