title: How to set boundaries on Map in MapKit IOS8 and Swift
body: <p>After a lot of research on this useful website, i put the guns down...</p>
  
  <p>I have a map with a lot of annotations.
  I will set boundaries in order to users stays on the wanted place.
  All documentations I've found were for Objective C and previous ios.</p>
  
  <p>I'm looking for a way to do it for IOS 8 and Swift pls.</p>