title: Duplicate zip entry retrofit-1.3.0
body: <p>I get an error when I try to create signed Apk with Proguard activated, relative to a duplicate zip entry with retrofit :</p>
  
  <pre><code>Note: there were 110 duplicate class definitions.
        (http://proguard.sourceforge.net/manual/troubleshooting.html#duplicateclass)
  Warning:can't write resource [.readme] (Duplicate zip entry [classes.jar:.readme])
  Warning:can't write resource [META-INF/LICENSE.txt] (Duplicate zip entry [commons-lang3-3.2.1.jar:META-INF/LICENSE.txt])
  Warning:can't write resource [META-INF/NOTICE.txt] (Duplicate zip entry [commons-lang3-3.2.1.jar:META-INF/NOTICE.txt])
  Warning:can't write resource [META-INF/LICENSE.txt] (Duplicate zip entry [commons-io-1.3.2.jar:META-INF/LICENSE.txt])
  Warning:can't write resource [META-INF/NOTICE.txt] (Duplicate zip entry [commons-io-1.3.2.jar:META-INF/NOTICE.txt])
  Warning:can't write resource [.readme] (Duplicate zip entry [classes.jar:.readme])
  :app:proguardAppRelease FAILED
  Error:Execution failed for task ':app:proguardAppRelease'.
  &gt; java.io.IOException: Can't write [/Users/me/Projects/myProject/app/build/intermediates/classes-proguard/app/release/classes.jar] (Can't read [/Users/me/Projects/myProject/app/build/intermediates/exploded-aar/myProject/mySubProject/unspecified/jars/libs/retrofit-1.3.0.jar(;;;;;;!META-INF/MANIFEST.MF)] (Duplicate zip entry [b/a/a.class == retrofit-1.3.0.jar:retrofit/android/AndroidApacheClient.class]))
  </code></pre>
  
  <p>Here my dependancies in my build.gradle :</p>
  
  <pre><code>dependencies {
      compile 'joda-time:joda-time:2.7'
      compile 'com.android.support:multidex:1.0.0'
      compile 'com.android.support:support-v4:19.1.0'
  
      compile 'com.google.code.gson:gson:2.2.4'
      compile('com.octo.android.robospice:robospice-retrofit:1.4.11') {
          exclude group: 'commons-io', module: 'commons-io'
      }
      compile('com.squareup.okhttp:okhttp:1.5.4')
      compile 'com.google.android.gms:play-services:5.0.89'
      compile 'com.splunk.mint:mint:4.0.5'
      compile fileTree(dir: 'libs', include: ['*.jar'])
      compile files('libs/PushLinkAndroid-5.3.0.jar')
      compile project(':mobihelp_sdk_android_v1.5.4')
  }
  </code></pre>
  
  <p>And also I have added this packaginOptions :</p>
  
  <pre><code> packagingOptions {
          exclude '.readme'
          exclude 'LICENSE.txt'
          exclude 'README.txt'
          exclude 'META-INF/notice.txt'
          exclude 'META-INF/license.txt'
          exclude 'META-INF/NOTICE.txt'
          exclude 'META-INF/LICENSE.txt'
          exclude 'META-INF/MANIFEST.MF'
      }
  </code></pre>
  
  <p>I would like to know if it's possible maybe to fix this problem by excluding retrofit-1.3.0 from my compile('com.octo.android.robospice:robospice-retrofit:1.4.11') or if there is another better solution.</p>