add workaround for annotations dependency conflict with espresso

}

</pre>

<div class="caution">

<p><strong>Caution:</strong> If your build configuration includes a

<code>compile</code> dependency for the <code>support-annotations</code>

library <b>and</b> an <code>androidTestCompile</code> dependency for the

<code>espresso-core</code> library, your build might fail due to a dependency

conflict. To resolve, update your dependency for <code>espresso-core</code>

as follows:</p>

<pre>

androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {

    exclude group: 'com.android.support', module: 'support-annotations'

})

</pre>

</div>

<p>

  To use JUnit 4 test classes, make sure to specify <a href=