title: gradle - library duplicates in dependencies
body: <p>I have an Android project with gradle. The problem is:
  In <code>project</code> view I see few versions of <code>support-v4</code> libraries, for example <code>support-v4-21.0.3</code> and <code>support-v4-22.2.0</code>.</p>
  
  <p><strong>But in <code>build.gradle</code> I don't have <code>support-v4</code> at all.</strong></p>
  
  <p>But I have ~10 other dependencies in <code>build.gradle</code>. For example 
  <code>appcompat-v7:22.2.0</code>. I can suggests that <code>appcompat-v7:22.2.0</code> depens on <code>support-v4-22.2.0</code> in maven dependencies and implicitly pulls it. But I have no ideas who pulls <code>support-v4-21.0.3</code>.</p>
  
  <p>As far as I know all this libs will packed in my APK and increase weight of APK. </p>
  
  <p>So I have next questions:</p>
  
  <ol>
  <li>How to avoid library duplicates?</li>
  <li>How to see maven dependencies in Android Studio? </li>
  <li>How detect which library require this library? For example which library require <code>support-v4-21.0.3</code> in my project?</li>
  </ol>