Objective C create 36 UUID
// generate 36 length UUID
// from: http://stackoverflow.com/questions/8684551/generate-a-uuid-string-with-arc-enabled
+ (NSString *)uuidString {
// Returns a UUID
CFUUIDRef uuid = CFUUIDCreate(kCFAllocatorDefault);
NSString *uuidStr = (__bridge_transfer NSString *)CFUUIDCreateString(kCFAllocatorDefault, uuid);
CFRelease(uuid);
return uuidStr;
}