title: iphone sdk: NSCFString does not match with value
body: <p>I am using Kinvey Kit in one of my apps. While using query <code>+(KCSQuery *)queryOnField:(NSString *)field withExactMatchForValue:(NSObject *)value</code>, I try matching record with KCSUser userId. It does not match by using self.userId but if I do <code>@"53a7ded611324c8002041603"</code>, it matches immediately. self.userId is same as <code>53a7ded611324c8002041603</code> except its type is NSCFString. </p>
  
  <p>Its driving me nuts. Is there anyway to change NSCFString to NSString.</p>