title: Automatically scroll screen in vim when near top/bottom?
body: <p>I would like to have smarter screen scrolling when I'm editing. When I reach within X number of lines from the top/bottom of the screen, I would like it to scroll the screen as I continue moving the cursor (so I can always see, at minimum, X lines below or above).</p>
  
  <p>I know <code>ctrl-y</code> and <code>ctrl-e</code> will scroll, but is there a way I can have vim detect when I hit <code>j</code> or <code>k</code> how far I am from the top/bottom of the screen so it can move the screen as needed?
   I also know <code>zz</code> will center on the current cursor location, but I'd like there to be an area where it doesn't scroll.</p>
  
  <p>Thanks.</p>