make CompletionCallback, SuccessCallback public
make CompletionCallback, SuccessCallback public

adding Swift and Xcode 7 beta 4 compatibility fix

zhaar/BrightFutures,MattesGroeger/BrightFutures,Thomvis/BrightFutures,Noobish1/BrightFutures,Thomvis/BrightFutures,tranhieutt/BrightFutures,Noobish1/BrightFutures,zhaar/BrightFutures,MattesGroeger/BrightFutures,tranhieutt/BrightFutures