title: ADT updation error
body: <p>How can I fix this error?</p>
  
  <pre><code>Cannot complete the install because of a conflicting dependency.
    Software being installed: Android Development Tools 23.0.7.2120684 (com.android.ide.eclipse.adt.feature.feature.group 23.0.7.2120684)
    Software currently installed: Android Development Tools 21.0.1.v201212060256-543035 (com.android.ide.eclipse.adt.feature.group 21.0.1.v201212060256-543035)
    Only one of the following can be installed at once: 
      ADT XML Overlay 23.0.7.2120684 (overlay.com.android.ide.eclipse.adt.overlay 23.0.7.2120684)
      ADT XML Overlay 21.0.1.v201212060256-543035 (overlay.com.android.ide.eclipse.adt.overlay 21.0.1.v201212060256-543035)
    Cannot satisfy dependency:
      From: Android Development Tools 23.0.7.2120684 (com.android.ide.eclipse.adt.feature.feature.group 23.0.7.2120684)
      To: overlay.com.android.ide.eclipse.adt.overlay [23.0.7.2120684]
    Cannot satisfy dependency:
      From: Android Development Tools 21.0.1.v201212060256-543035 (com.android.ide.eclipse.adt.feature.group 21.0.1.v201212060256-543035)
      To: overlay.com.android.ide.eclipse.adt.overlay [21.0.1.v201212060256-543035]
  </code></pre>