title: setting multiple sort descriptors
body: <p>I have a array of objects and need to sort it by rating and after by number of votes descendent(so that if two 5 stars rated elements compare, the one with the most votes should be first) </p>
  
  <p>Is it possible to sort a NSArray by two descriptors:first after rating and then after votes count? </p>
  
  <p>I've found on <a href="http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSSortDescriptor_Class/Reference/Reference.html" rel="nofollow noreferrer">http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSSortDescriptor_Class/Reference/Reference.html</a></p>
  
  <p>something like <code>sortUsingDescriptors:</code> but i can't find it anywhere in the docs, think it's deprecated. </p>