title: Conflict with dependency 'com.android.support:support-annotations'. Resolved versions for app (23.1.0) and test app (23.0.1) differ
body: <p>When building I get the following error: </p>
  
  <pre><code>Conflict with dependency 'com.android.support:support-annotations'. Resolved versions for app (23.1.0) and test app (23.0.1) differ.
  </code></pre>
  
  <p>These are my gradle dependencies</p>
  
  <pre><code>dependencies {
      compile fileTree(include: ['*.jar'], dir: 'libs')
      compile 'com.android.support:support-v4:23.1.0'
      compile 'com.android.support:appcompat-v7:23.1.0'
      compile 'com.android.support:design:23.1.0'
      compile 'com.android.support:cardview-v7:23.1.0'
      compile 'com.android.support:recyclerview-v7:23.1.0'
      compile 'com.squareup.retrofit:retrofit:1.9.0'
      compile 'com.squareup.okhttp:okhttp:2.4.0'
      compile 'com.squareup.picasso:picasso:2.5.2'
      compile 'com.jakewharton:butterknife:7.0.1'
      compile 'com.squareup:otto:1.3.8'
      compile 'com.snappydb:snappydb-lib:0.5.2'
      compile 'com.esotericsoftware.kryo:kryo:2.24.0'
      compile 'com.google.dagger:dagger:2.0.1'
      apt 'com.google.dagger:dagger-compiler:2.0.1'
      compile 'javax.annotation:javax.annotation-api:1.2'
      compile 'io.reactivex:rxandroid:1.0.1'
      compile 'io.reactivex:rxjava:1.0.14'
      compile 'com.google.android.gms:play-services-location:8.1.0'
      compile 'com.google.android.gms:play-services-gcm:8.1.0'
      compile 'org.apache.commons:commons-lang3:3.4'
      testCompile 'junit:junit:4.12'
      testCompile 'org.hamcrest:hamcrest-library:1.3'
      testCompile 'org.mockito:mockito-core:1.10.19'
      androidTestCompile 'com.android.support.test:runner:0.4'
      androidTestCompile 'com.android.support.test:rules:0.4'
      androidTestCompile 'com.android.support.test.espresso:espresso-core:2.2.1'
      androidTestCompile 'com.android.support.test.espresso:espresso-intents:2.2.1'
      androidTestCompile 'com.android.support.test.espresso:espresso-web:2.2.1'
      debugCompile 'com.squareup.leakcanary:leakcanary-android:1.3.1'
      releaseCompile 'com.squareup.leakcanary:leakcanary-android-no-op:1.3.1'
  }
  </code></pre>
  
  <p>How can I fix this?</p>