title: How to find the closest point in the DB using objectify-appengine
body: <p>I'm using objectify-appengine in my app. In the DB I store latitude &amp; longitude of places.
  at some point I'd like to find the closest place (from the DB) to a specific point. <br/>
  As far as i understood i can't perform regular SQL-like queries. 
  So my question is how can it be done in the best way?</p>