title: ViewPager.setOffscreenPageLimit(0) doesn't work as expected
body: <p>The fragments I use in my <code>ViewPager</code> instance are quite resource intensive, so I'd only like to load one at a time. When I try the following:</p>
  
  <pre><code>mViewPager.setOffscreenPageLimit(0);
  mViewPager.setAdapter(mPagerAdapter);
  </code></pre>
  
  <p>My <code>FragmentStatePagerAdapter.getItem(int position)</code> override function is called 3 times, which is what happens when I call <code>mViewPager.setOffscreenPageLimit(1)</code>. I would expect it to only be called once, because I specified 0 offscreen pages. </p>
  
  <p>I believe I'm calling everything correctly, because if I call <code>mViewPager.setOffscreenPageLimit(2)</code>, <code>FragmentStatePagerAdapter.getItem(int position)</code> is called 5 times as I would expect. </p>
  
  <p>Does ViewPager require a minimum of 1 offscreen pages, or am I doing something wrong here? </p>