made more Swift 2 change
made more Swift 2 change

f22x/Just,jianwoo/Just,sunfei/Just,JustHTTP/Just,alvinvarghese/Just,alvinvarghese/Just,alvinvarghese/Just,msdgwzhy6/Just,sunfei/Just,f22x/Just,msdgwzhy6/Just,jianwoo/Just,msdgwzhy6/Just,sunfei/Just,JustHTTP/Just,jianwoo/Just,f22x/Just