title: Activity not registered in the manifest Lint warning
body: <p>I have a base activity from which I subclass several other activities.</p>
  
  <p>Those other activities I do register in the manifest so I can use them from within my application.</p>
  
  <p>However, Android inspection says, for my base activity, <code>"Activity not registered in the manifest"</code>.</p>
  
  <p>I see no reason to register the base activity as I never use it directly. However, maybe, I am missing something and the warning should not be ignored?</p>
  
  <p>Why this warning anyway?</p>