title: Check whether or not user is in Location boundaries
body: <p>I am using Geofencing.  I want a method that checks whether or not a user is within certain boundaries.</p>
  
  <p>I have the location as a <code>CLLocationCoordinate2D</code> which I've named <code>location</code>, and I have an array of 8 doubles, making up 4 coordinates (NW, NE, SW, SE).  I can convert them to <code>CLLocationCoordinate2D</code>'s.  My question is, how can I check whether the <code>location</code> is within the boundaries? in iOS...</p>