title: Remove title in Toolbar in appcompat-v7
body: <p>The <a href="https://developer.android.com/reference/android/support/v7/widget/Toolbar.html" rel="noreferrer">documentation</a> of <code>Toolbar</code> says</p>
  
  <blockquote>
    <p>If an app uses a logo image it should strongly consider omitting a title and subtitle.</p>
  </blockquote>
  
  <p>What is the proper way to remove the title?</p>