am f151391b: fix markup errors in action bar styling, add more information...

am f151391b: fix markup errors in action bar styling, add more information about using drawables, move \'managing the activity lifecycle\' down a notch, because it\'s less interesting.

* commit 'f151391b':
  fix markup errors in action bar styling, add more information about using drawables, move 'managing the activity lifecycle' down a notch, because it's less interesting.