title: How to create a circle drawable?
body: <p>How to a create a <code>drawable</code> of a circle, with blue stroke of 5 pixels and a transparent fill.</p>
  
  <p>I will be passing this <code>drawable</code> to an <code>ItemizedOverlay</code> .</p>
  
  <p>I want to do this with code and I will know the radius of the circle.</p>